### 기본 TCP 서버```c
#include "socket/Socket.h"
#include "core/Except.h"
#include <stdio.h>

int main(void)
{
    Socket_T server = Socket_new(AF_INET, SOCK_STREAM, 0);
    
    TRY
        Socket_setreuseaddr(server);
        Socket_bind(server, NULL, 8080);
        Socket_listen(server, 128);
        printf("Server listening on port 8080...\n");
        
        while (1) {
            Socket_T client = Socket_accept(server);
            if (client) {
                char buf[1024];
                ssize_t n = Socket_recv(client, buf, sizeof(buf) - 1);
                if (n > 0) {
                    buf[n] = '\0';
                    Socket_sendall(client, buf, n);
                }
                Socket_free(&client);
            }
        }
    EXCEPT(Socket_Failed)
        fprintf(stderr, "Error: %s\n", Socket_GetLastError());
    END_TRY;
    
    Socket_free(&server);
    return 0;
}

TRY
    Socket_connect(client, "127.0.0.1", 8080);
    printf("Connected to server\n");
    
    const char *msg = "Hello, Server!";
    Socket_sendall(client, msg, strlen(msg));
    
    char buf[1024];
    ssize_t n = Socket_recvall(client, buf, strlen(msg));
    buf[n] = '\0';
    printf("Received: %s\n", buf);
EXCEPT(Socket_Failed)
    fprintf(stderr, "Error: %s\n", Socket_GetLastError());
EXCEPT(Socket_Closed)
    fprintf(stderr, "Connection closed\n");
END_TRY;

Socket_free(&client);
return 0;

### 편의 함수 (단일 호출 설정)

일반적인 사용 사례를 위해 편의 함수가 소켓 설정을 간소화합니다:```c
#include "socket/Socket.h"
#include "socket/SocketDgram.h"

/* TCP Server - one call creates listening socket */
Socket_T server = Socket_listen_tcp("0.0.0.0", 8080, 128);
while (running) {
    Socket_T client = Socket_accept_timeout(server, 1000);  // 1s timeout
    if (client) handle_client(client);
}
Socket_free(&server);

/* TCP Client with timeout - one call connects */
Socket_T client = Socket_connect_tcp("api.example.com", 443, 5000);  // 5s timeout
Socket_sendall(client, request, len);
Socket_free(&client);

/* UDP Server - one call binds */
SocketDgram_T udp = SocketDgram_bind_udp("0.0.0.0", 5353);
SocketDgram_recvfrom(udp, buf, sizeof(buf), sender_ip, sizeof(sender_ip), &sender_port);
SocketDgram_free(&udp);

/* Unix Domain Server */
Socket_T unix_srv = Socket_listen_unix("/var/run/app.sock", 128);
Socket_free(&unix_srv);

/* Unix Domain Client with timeout */
Socket_T unix_cli = Socket_new(AF_UNIX, SOCK_STREAM, 0);
Socket_connect_unix_timeout(unix_cli, "/var/run/app.sock", 5000);
Socket_free(&unix_cli);

/* Non-blocking connect (for event loops) */
Socket_T sock = Socket_new(AF_INET, SOCK_STREAM, 0);
int status = Socket_connect_nonblocking(sock, "192.168.1.1", 8080);
if (status == 1) {
    /* In progress - poll for POLL_WRITE then check Socket_isconnected() */
}

전체 API 문서는 [docs/simple.md](https://github.com/7etsuo/tetsuo-pulse/blob/HEAD/docs/simple.md)를 참조하세요.

## 사용 패턴

### 오류 처리

모든 소켓 작업은 예외 기반 오류 처리를 사용합니다:```c
TRY
    Socket_connect(socket, "example.com", 80);
    Socket_sendall(socket, data, len);
EXCEPT(Socket_Failed)
    if (Socket_error_is_retryable(Socket_geterrno()))
        /* Schedule retry with backoff */
    else
        fprintf(stderr, "Fatal error: %s\n", Socket_Failed.reason);
EXCEPT(Socket_Closed)
    fprintf(stderr, "Connection closed\n");
FINALLY
    Socket_free(&socket);
END_TRY;

for (int i = 0; i < n; i++) {
    if (events[i].socket == server) {
        Socket_T client = Socket_accept(server);
        if (client) {
            Socket_setnonblocking(client);
            SocketPoll_add(poll, client, POLL_READ, client);
        }
    } else {
        Socket_T client = events[i].socket;
        char buf[1024];
        ssize_t bytes = Socket_recv(client, buf, sizeof(buf));
        if (bytes > 0) {
            Socket_sendall(client, buf, bytes);
        } else {
            SocketPoll_del(poll, client);
            Socket_free(&client);
        }
    }
}

### HTTP 클라이언트```c
#include "http/SocketHTTPClient.h"

/* Simple GET request */
SocketHTTPClient_T client = SocketHTTPClient_new(NULL);
SocketHTTPClient_Response response = {0};

if (SocketHTTPClient_get(client, "https://example.com/api", &response) == 0) {
    printf("Status: %d\n", response.status_code);
    printf("Body: %.*s\n", (int)response.body_len, (char *)response.body);
}
SocketHTTPClient_Response_free(&response);

/* Request builder pattern */
SocketHTTPClient_Request_T req = SocketHTTPClient_Request_new(
    client, HTTP_METHOD_POST, "https://api.example.com/data");
SocketHTTPClient_Request_header(req, "Content-Type", "application/json");
SocketHTTPClient_Request_body(req, "{\"key\": \"value\"}", 16);
SocketHTTPClient_Request_timeout(req, 30000);

if (SocketHTTPClient_Request_execute(req, &response) == 0) {
    printf("POST Status: %d\n", response.status_code);
}
SocketHTTPClient_Request_free(&req);
SocketHTTPClient_Response_free(&response);

/* Cookie jar */
SocketHTTPClient_CookieJar_T jar = SocketHTTPClient_CookieJar_new();
SocketHTTPClient_set_cookie_jar(client, jar);

SocketHTTPClient_free(&client);

### HTTP 서버

HTTP/2 협상(ALPN vs h2c vs prior-knowledge), stream lifecycle, trailers, GOAWAY/drain, 및 RFC 8441 상태에 대한 자세한 내용은 `docs/HTTP2-SERVER.md`를 참조하십시오.```c
#include "http/SocketHTTPServer.h"
#include "http/SocketHTTP.h"
#include <string.h>

static void
handle_request (SocketHTTPServer_Request_T req, void *userdata)
{
    (void)userdata;

    if (SocketHTTPServer_Request_method (req) == HTTP_METHOD_GET
        && strcmp (SocketHTTPServer_Request_path (req), "/") == 0)
      {
        SocketHTTPServer_Request_status (req, 200);
        SocketHTTPServer_Request_header (req, "content-type", "text/html");
        SocketHTTPServer_Request_body_string (req, "<h1>Hello World</h1>");
        SocketHTTPServer_Request_finish (req);
        return;
      }

    SocketHTTPServer_Request_status (req, 404);
    SocketHTTPServer_Request_body_string (req, "Not Found");
    SocketHTTPServer_Request_finish (req);
}

int
main (void)
{
    SocketHTTPServer_Config config;
    SocketHTTPServer_T server;

    SocketHTTPServer_config_defaults (&config);
    config.port = 8080;
    config.max_version = HTTP_VERSION_2;   /* Allow HTTP/2 (default) */
    config.enable_h2c_upgrade = 0;         /* h2c is opt-in */

    server = SocketHTTPServer_new (&config);
    SocketHTTPServer_set_handler (server, handle_request, NULL);
    SocketHTTPServer_start (server);

    /* Event loop */
    for (;;)
      SocketHTTPServer_process (server, 1000);
}

### WebSocket Client```c
#include "socket/SocketWS.h"

/* One-liner WebSocket connection (new convenience API) */
SocketWS_T ws = SocketWS_connect("wss://echo.websocket.org", NULL);
if (ws) {
    /* Send and receive JSON messages */
    SocketWS_send_json(ws, "{\"type\": \"hello\", \"data\": \"world\"}");
    
    char *json = NULL;
    size_t len;
    if (SocketWS_recv_json(ws, &json, &len) == WS_OK) {
        printf("Received: %s\n", json);
        free(json);
    }
    
    /* Check ping latency */
    SocketWS_ping(ws, "test", 4);
    SocketWS_process(ws, POLLIN);  /* Wait for pong */
    int64_t rtt = SocketWS_get_ping_latency(ws);
    printf("Latency: %lld ms\n", (long long)rtt);
    
    SocketWS_close(ws, WS_CLOSE_NORMAL, "Goodbye", 7);
    SocketWS_free(&ws);
}

/* Traditional multi-step connection */
Socket_T sock = Socket_new(AF_INET, SOCK_STREAM, 0);
Socket_connect(sock, "echo.websocket.org", 80);

SocketWS_Config ws_config = SOCKETWS_CONFIG_DEFAULTS;
SocketWS_T ws2 = SocketWS_client_new(sock, "echo.websocket.org", "/", &ws_config);

/* Enable compression before handshake */
SocketWS_CompressionOptions comp_opts;
SocketWS_compression_options_defaults(&comp_opts);
comp_opts.level = 9;  /* Maximum compression */
SocketWS_enable_compression(ws2, &comp_opts);

/* Perform handshake */
TRY
    SocketWS_handshake(ws2);
    
    /* Send text message */
    SocketWS_send_text(ws2, "Hello, WebSocket!", 17);
    
    /* Graceful close */
    SocketWS_close(ws2, WS_CLOSE_NORMAL, "Goodbye", 7);
EXCEPT(SocketWS_Failed)
    fprintf(stderr, "WebSocket error: %s\n", SocketWS_Failed.reason);
END_TRY;

SocketWS_free(&ws2);
Socket_free(&sock);

### 프록시 터널링```c
#include "socket/SocketProxy.h"

/* SOCKS5 proxy configuration */
SocketProxy_Config proxy = {0};
proxy.type = SOCKET_PROXY_SOCKS5;
proxy.host = "proxy.example.com";
proxy.port = 1080;
proxy.username = "user";
proxy.password = "secret";

Socket_T sock = Socket_new(AF_INET, SOCK_STREAM, 0);

/* Connect through proxy (synchronous) */
SocketProxy_Result result = SocketProxy_connect(sock, &proxy, "target.example.com", 443);
if (result == PROXY_OK) {
    /* Socket is now tunneled - proceed with TLS handshake if needed */
    SocketTLS_enable(sock, tls_ctx);
    SocketTLS_handshake_loop(sock, 10000);
}

/* HTTP CONNECT proxy */
SocketProxy_Config http_proxy = {0};
http_proxy.type = SOCKET_PROXY_HTTP;
http_proxy.host = "httpproxy.example.com";
http_proxy.port = 8080;
http_proxy.username = "user";
http_proxy.password = "pass";

/* Asynchronous proxy connection */
SocketProxy_Conn_T conn = SocketProxy_Conn_new(sock, &http_proxy, "target.com", 443);
while (!SocketProxy_Conn_poll(conn)) {
    int timeout = SocketProxy_Conn_next_timeout_ms(conn);
    SocketPoll_wait(poll, &events, timeout);
    SocketProxy_Conn_process(conn);
}
result = SocketProxy_Conn_result(conn);
SocketProxy_Conn_free(&conn);

char buf[1024];
ssize_t n = SocketDTLS_recv(sock, buf, sizeof(buf));

### UDP 서버```c
#include "socket/SocketDgram.h"

SocketDgram_T server = SocketDgram_new(AF_INET, 0);
SocketDgram_bind(server, NULL, 5000);

char buffer[65536];
char sender_host[46];
int sender_port;

while (1) {
    ssize_t n = SocketDgram_recvfrom(server, buffer, sizeof(buffer),
                                     sender_host, sizeof(sender_host),
                                     &sender_port);
    if (n > 0) {
        /* Echo back to sender */
        SocketDgram_sendto(server, buffer, n, sender_host, sender_port);
    }
}

SocketDgram_free(&server);

### 연결 풀 통계 및 필터링```c
#include "pool/SocketPool.h"

/* Get pool statistics */
SocketPool_Stats stats;
SocketPool_get_stats(pool, &stats);
printf("Active: %zu, Idle: %zu, Reuse rate: %.1f%%\n",
       stats.current_active, stats.current_idle, stats.reuse_rate * 100.0);

/* Convenience stat functions */
size_t active = SocketPool_get_active_count(pool);
size_t idle = SocketPool_get_idle_count(pool);
double hit_rate = SocketPool_get_hit_rate(pool);

/* Find connections matching criteria */
int is_from_subnet(Connection_T conn, void *data) {
    const char *subnet = (const char *)data;
    return strncmp(Socket_getpeeraddr(Connection_socket(conn)), subnet, 7) == 0;
}

/* Find first matching connection */
Connection_T conn = SocketPool_find(pool, is_from_subnet, "192.168");

/* Get all matching connections */
Connection_T matches[100];
size_t count = SocketPool_filter(pool, is_from_subnet, "192.168", matches, 100);
for (size_t i = 0; i < count; i++) {
    /* Process matching connections */
}

/* Register idle callback */
void on_idle(Connection_T conn, void *data) {
    printf("Connection went idle: %s\n",
           Socket_getpeeraddr(Connection_socket(conn)));
}
SocketPool_set_idle_callback(pool, on_idle, NULL);

/* Shrink pool to release unused memory */
size_t released = SocketPool_shrink(pool);
printf("Released %zu unused slots\n", released);

/* Reset statistics for new measurement window */
SocketPool_reset_stats(pool);

### SYN 플러드 보호```c
#include "core/SocketSYNProtect.h"

SocketSYNProtect_Config config = SYNPROTECT_CONFIG_DEFAULTS;
config.max_connections_per_ip = 10;
config.connection_rate_limit = 100;
config.challenge_threshold = 0.5;  /* Reputation score threshold */
config.block_threshold = 0.2;

SocketSYNProtect_T protect = SocketSYNProtect_new(NULL, &config);

/* On each incoming connection */
struct sockaddr_in client_addr;
socklen_t addr_len = sizeof(client_addr);
int client_fd = accept(server_fd, (struct sockaddr *)&client_addr, &addr_len);

SYNAction action = SocketSYNProtect_check(protect, &client_addr, addr_len);

switch (action) {
case SYN_ACTION_ALLOW:
    /* Accept connection normally */
    break;
case SYN_ACTION_THROTTLE:
    /* Accept but add delay */
    usleep(100000);
    break;
case SYN_ACTION_CHALLENGE:
    /* Send SYN cookie / challenge */
    break;
case SYN_ACTION_BLOCK:
    /* Reject connection */
    close(client_fd);
    break;
}

/* Report connection result for reputation update */
SocketSYNProtect_report(protect, &client_addr, addr_len, success);

/* Get statistics */
SocketSYNProtect_Stats stats;
SocketSYNProtect_stats(protect, &stats);

SocketSYNProtect_free(&protect);

### Happy Eyeballs Connection (RFC 8305)```c
#include "socket/SocketHappyEyeballs.h"

/* Synchronous - races IPv6 and IPv4 for fastest connection */
Socket_T sock = SocketHappyEyeballs_connect("example.com", 443, NULL);
Socket_sendall(sock, "GET / HTTP/1.1\r\n\r\n", 18);
Socket_free(&sock);

/* Asynchronous - for event-driven applications */
SocketHE_Config_T config;
SocketHappyEyeballs_config_defaults(&config);
config.first_attempt_delay_ms = 250;  /* RFC 8305 default */
config.total_timeout_ms = 30000;

SocketHE_T he = SocketHappyEyeballs_start(dns, poll, "example.com", 443, &config);
while (!SocketHappyEyeballs_poll(he)) {
    int timeout = SocketHappyEyeballs_next_timeout_ms(he);
    SocketPoll_wait(poll, &events, timeout);
    SocketHappyEyeballs_process(he);
}
Socket_T result = SocketHappyEyeballs_result(he);
SocketHappyEyeballs_free(&he);

if (SocketReconnect_isconnected(conn)) {
    /* I/O with auto-reconnect on error */
    ssize_t n = SocketReconnect_send(conn, data, len);
}

### 일반 재시도 프레임워크```c
#include "core/SocketRetry.h"

/* Configure retry policy */
SocketRetry_Policy policy;
SocketRetry_policy_defaults(&policy);
policy.max_attempts = 5;
policy.initial_delay_ms = 100;
policy.max_delay_ms = 30000;
policy.multiplier = 2.0;
policy.jitter = 0.25;

/* Define operation to retry */
int connect_op(void *ctx, int attempt) {
    ConnectionCtx *c = ctx;
    return connect(c->fd, c->addr, c->addrlen) < 0 ? errno : 0;
}

/* Define retry decision callback */
int should_retry(int err, int attempt, void *ctx) {
    return SocketError_is_retryable_errno(err);
}

/* Execute with retries */
SocketRetry_T retry = SocketRetry_new(&policy);
int result = SocketRetry_execute(retry, connect_op, should_retry, &ctx);

/* Get statistics */
SocketRetry_Stats stats;
SocketRetry_get_stats(retry, &stats);
printf("Attempts: %d, Total delay: %lld ms\n", stats.attempts, stats.total_delay_ms);

SocketRetry_free(&retry);

### 비동기 I/O (io_uring/kqueue)```c
#include "socket/SocketAsync.h"
#include "poll/SocketPoll.h"

/* Check what backend is available */
if (SocketAsync_backend_available(ASYNC_BACKEND_IO_URING)) {
    printf("io_uring available - optimal async I/O\n");
} else if (SocketAsync_backend_available(ASYNC_BACKEND_KQUEUE)) {
    printf("kqueue available - good async I/O\n");
} else {
    printf("Using poll-based fallback\n");
}

/* Set preferred backend (optional) */
SocketAsync_set_backend(ASYNC_BACKEND_IO_URING);

/* Get async context from poll */
SocketPoll_T poll = SocketPoll_new(1024);
SocketAsync_T async = SocketPoll_get_async(poll);

/* Completion callback */
void io_complete(Socket_T socket, ssize_t bytes, int err, void *ud) {
    if (err) {
        printf("Error: %s\n", strerror(err));
        return;
    }
    printf("Transferred %zd bytes\n", bytes);
}

/* Submit async send */
unsigned req_id = SocketAsync_send(async, socket, buf, len,
                                   io_complete, userdata, ASYNC_FLAG_NONE);

/* Submit async recv */
req_id = SocketAsync_recv(async, socket, recv_buf, sizeof(recv_buf),
                          io_complete, userdata, ASYNC_FLAG_ZERO_COPY);

/* Batch submission for efficiency */
SocketAsync_Op ops[3] = {
    {sock1, 1, send_buf, NULL, len1, io_complete, ud1, ASYNC_FLAG_NONE, 0},
    {sock2, 0, NULL, recv_buf, len2, io_complete, ud2, ASYNC_FLAG_NONE, 0},
    {sock3, 1, send_buf2, NULL, len3, io_complete, ud3, ASYNC_FLAG_URGENT, 0}
};
int submitted = SocketAsync_submit_batch(async, ops, 3);
printf("Submitted %d operations\n", submitted);

/* Cancel specific operation */
SocketAsync_cancel(async, req_id);

/* Cancel all pending (during shutdown) */
int cancelled = SocketAsync_cancel_all(async);
printf("Cancelled %d pending ops\n", cancelled);

/* Check backend in use */
printf("Backend: %s, available: %s\n",
       SocketAsync_backend_name(async),
       SocketAsync_is_available(async) ? "yes" : "fallback");

/* Completions auto-processed in SocketPoll_wait() */
SocketEvent_T *events;
int n = SocketPoll_wait(poll, &events, 100);

SocketPoll_free(&poll);

### 연결 상태 및 프로빙```c
#include "socket/Socket.h"

Socket_T sock = Socket_new(AF_INET, SOCK_STREAM, 0);
Socket_connect(sock, "example.com", 80);

/* Quick health check (non-blocking) */
if (!Socket_probe(sock, 0)) {
    printf("Connection appears dead\n");
}

/* Health check with timeout (waits up to 100ms for response) */
if (!Socket_probe(sock, 100)) {
    printf("Connection lost, reconnecting...\n");
}

/* Check for pending socket errors (after non-blocking connect) */
int error = Socket_get_error(sock);
if (error != 0) {
    printf("Socket error: %s\n", strerror(error));
}

/* Check read/write readiness without blocking */
if (Socket_is_readable(sock) > 0) {
    char buf[1024];
    ssize_t n = Socket_recv(sock, buf, sizeof(buf));
}

if (Socket_is_writable(sock) > 0) {
    Socket_send(sock, "GET / HTTP/1.1\r\n\r\n", 18);
}

#ifdef __linux__
/* Get TCP stack statistics (Linux only) */
SocketTCPInfo info;
if (Socket_get_tcp_info(sock, &info) == 0) {
    printf("RTT: %.2f ms\n", info.rtt_us / 1000.0);
    printf("Congestion window: %u segments\n", info.snd_cwnd);
    printf("Retransmissions: %u\n", info.total_retrans);
    if (info.delivery_rate > 0) {
        printf("Delivery rate: %.2f Mbps\n", info.delivery_rate * 8.0 / 1e6);
    }
}
#endif

/* Simple RTT query (cross-platform, returns -1 if unavailable) */
int32_t rtt = Socket_get_rtt(sock);
if (rtt >= 0) {
    printf("RTT: %.2f ms\n", rtt / 1000.0);
}

/* Congestion window query (Linux only) */
int32_t cwnd = Socket_get_cwnd(sock);
if (cwnd >= 0) {
    printf("CWND: %d segments\n", cwnd);
}

Socket_free(&sock);

### 고급 I/O 작업```c
#include "socket/Socket.h"

/* Peek at data without consuming */
char peek_buf[16];
ssize_t peeked = Socket_peek(sock, peek_buf, sizeof(peek_buf));
if (peeked > 0) {
    printf("Peeked %zd bytes: protocol=%d\n", peeked, peek_buf[0]);
}

/* TCP cork for efficient message assembly */
Socket_cork(sock, 1);  /* Enable corking */
Socket_send(sock, headers, header_len);
Socket_send(sock, body, body_len);
Socket_cork(sock, 0);  /* Disable cork, flush all data */

#ifdef __linux__
/* Zero-copy socket-to-socket transfer (Linux only) */
ssize_t spliced = Socket_splice(client, upstream, 65536);
if (spliced > 0) {
    printf("Spliced %zd bytes\n", spliced);
} else if (spliced == 0) {
    /* Would block - poll for readiness */
} else {
    /* Not supported on this platform */
    char buf[4096];
    while ((n = Socket_recv(client, buf, sizeof(buf))) > 0) {
        Socket_sendall(upstream, buf, n);
    }
}
#endif

### 타이머```c
#include "poll/SocketPoll.h"
#include "core/SocketTimer.h"

SocketPoll_T poll = SocketPoll_new(100);

/* Check which backend is in use */
printf("Backend: %s\n", SocketPoll_get_backend_name(poll));
// Output: "epoll" (Linux), "kqueue" (macOS/BSD), or "poll" (fallback)

void timer_callback(void *userdata) {
    printf("Timer fired!\n");
}

/* One-shot timer (fires once after 5 seconds) */
SocketTimer_T timer = SocketTimer_add(poll, 5000, timer_callback, NULL);

/* Repeating timer (fires every 1 second) */
SocketTimer_T heartbeat = SocketTimer_add_repeating(poll, 1000, timer_callback, NULL);

/* Check remaining time */
int64_t remaining = SocketTimer_remaining(poll, timer);

/* Reschedule timer with new delay (extends/shortens timeout) */
SocketTimer_reschedule(poll, timer, 10000);  /* Now fires in 10 seconds */

/* Pause and resume timers */
SocketTimer_pause(poll, heartbeat);   /* Stops firing, preserves remaining time */
/* ... do something ... */
SocketTimer_resume(poll, heartbeat);  /* Continues from where it paused */

/* Cancel timer */
SocketTimer_cancel(poll, heartbeat);

/* Modify events for registered sockets */
Socket_T sock = /* ... */;
SocketPoll_add(poll, sock, POLL_READ, NULL);
SocketPoll_modify_events(poll, sock, POLL_WRITE, 0);  /* Add write monitoring */
SocketPoll_modify_events(poll, sock, 0, POLL_WRITE);  /* Remove write monitoring */

/* List registered sockets */
Socket_T sockets[100];
int count = SocketPoll_get_registered_sockets(poll, sockets, 100);
printf("Monitoring %d sockets\n", count);

/* Timers fire automatically during SocketPoll_wait() */
SocketEvent_T *events;
int n = SocketPoll_wait(poll, &events, -1);

SocketPoll_free(&poll);

### TLS/SSL 보안 통신```c
#include "tls/SocketTLS.h"
#include "tls/SocketTLSContext.h"

/* Create client TLS context */
SocketTLSContext_T ctx = SocketTLSContext_new_client("/etc/ssl/certs/ca-certificates.crt");

/* Configure ALPN protocols */
const char *protos[] = {"h2", "http/1.1"};
SocketTLSContext_set_alpn_protos(ctx, protos, 2);

/* Enable session caching for performance */
SocketTLSContext_enable_session_cache(ctx, 1000, 300);

/* Create and connect socket */
Socket_T socket = Socket_new(AF_INET, SOCK_STREAM, 0);
Socket_connect(socket, "example.com", 443);

/* Enable TLS */
SocketTLS_enable(socket, ctx);
SocketTLS_set_hostname(socket, "example.com");  /* SNI + verification */

/* Perform handshake (with timeout) */
TLSHandshakeState state = SocketTLS_handshake_loop(socket, 10000);
if (state != TLS_HANDSHAKE_COMPLETE) {
    fprintf(stderr, "Handshake failed\n");
}

/* Check negotiated protocol */
const char *alpn = SocketTLS_get_alpn_selected(socket);
printf("ALPN: %s\n", alpn ? alpn : "none");
printf("Cipher: %s\n", SocketTLS_get_cipher(socket));
printf("Version: %s\n", SocketTLS_get_version(socket));

/* Encrypted I/O */
SocketTLS_send(socket, "GET / HTTP/1.1\r\n\r\n", 18);
char buf[4096];
ssize_t n = SocketTLS_recv(socket, buf, sizeof(buf));

/* Graceful shutdown */
SocketTLS_shutdown(socket);
Socket_free(&socket);
SocketTLSContext_free(&ctx);

### TLS 인증서 정보```c
#include "tls/SocketTLS.h"

/* Get full certificate details */
SocketTLS_CertInfo info;
if (SocketTLS_get_peer_cert_info(sock, &info) == 1) {
    printf("Subject: %s\n", info.subject);
    printf("Issuer: %s\n", info.issuer);
    printf("Version: X.509v%d\n", info.version);
    printf("Serial: %s\n", info.serial);
    printf("Fingerprint: %s\n", info.fingerprint);
    printf("Valid from: %s", ctime(&info.not_before));
    printf("Valid until: %s", ctime(&info.not_after));
}

/* Quick certificate expiry check */
time_t expiry = SocketTLS_get_cert_expiry(sock);
if (expiry != (time_t)-1) {
    time_t now = time(NULL);
    int days_left = (expiry - now) / 86400;
    if (days_left < 30) {
        printf("Warning: Certificate expires in %d days!\n", days_left);
    }
}

/* Just get subject for logging */
char subject[256];
if (SocketTLS_get_cert_subject(sock, subject, sizeof(subject)) > 0) {
    printf("Connected to: %s\n", subject);
}

### SNI 및 인증서 핀잉을 사용하는 TLS 서버```c
#include "tls/SocketTLSContext.h"

/* Create server context with primary certificate */
SocketTLSContext_T ctx = SocketTLSContext_new_server(
    "server.crt", "server.key", "ca-bundle.crt");

/* Add SNI certificates for virtual hosting */
SocketTLSContext_add_certificate(ctx, "www.example.com", 
                                  "www.crt", "www.key");
SocketTLSContext_add_certificate(ctx, "api.example.com",
                                  "api.crt", "api.key");

/* Enable client certificate verification */
SocketTLSContext_set_verify_mode(ctx, TLS_VERIFY_PEER);

/* Load CRL for revocation checking */
SocketTLSContext_load_crl(ctx, "/path/to/crl.pem");

/* Enable OCSP stapling */
unsigned char ocsp_response[4096];
size_t ocsp_len = load_ocsp_response(ocsp_response, sizeof(ocsp_response));
SocketTLSContext_set_ocsp_response(ctx, ocsp_response, ocsp_len);

/* Enable session tickets */
unsigned char ticket_key[80];
generate_ticket_key(ticket_key, sizeof(ticket_key));
SocketTLSContext_enable_session_tickets(ctx, ticket_key, sizeof(ticket_key));

/* Certificate pinning (client context) */
SocketTLSContext_T client_ctx = SocketTLSContext_new_client("ca-bundle.pem");
SocketTLSContext_add_pin_hex(client_ctx, 
    "b5bb9d8014a0f9b1d61e21e796d78dccdf1352f23cd32812f4850b878ae4944c");
SocketTLSContext_set_pin_enforcement(client_ctx, 1);  /* Strict mode */

### OCSP Must-Staple (RFC 7633)```c
#include "tls/SocketTLSContext.h"

/* Create client context with must-staple enforcement */
SocketTLSContext_T ctx = SocketTLSContext_new_client("ca-bundle.pem");

/* Auto-detection: respect certificate's must-staple extension */
SocketTLSContext_set_ocsp_must_staple(ctx, OCSP_MUST_STAPLE_AUTO);

/* Or always require OCSP stapling for strict security policies */
SocketTLSContext_set_ocsp_must_staple(ctx, OCSP_MUST_STAPLE_ALWAYS);

/* Query current mode */
OCSPMustStapleMode mode = SocketTLSContext_get_ocsp_must_staple(ctx);

/* Connect and handshake - fails if must-staple cert has no OCSP response */
SocketTLS_enable(sock, ctx);
SocketTLS_handshake_auto(sock);

**kTLS 요구 사항:**
| 기능 | 요구 사항 |
|---------|-------------|
| TX offload | Linux 4.13+, OpenSSL 3.0+ with enable-ktls |
| RX offload | Linux 4.17+ |
| ChaCha20 | Linux 5.11+ |
| Ciphers | AES-GCM-128/256, ChaCha20-Poly1305 |

### TLS 1.3 0-RTT Early Data```c
#include "tls/SocketTLS.h"
#include "tls/SocketTLSContext.h"

/* Server: Enable 0-RTT early data reception */
SocketTLSContext_T srv_ctx = SocketTLSContext_new_server("cert.pem", "key.pem", NULL);
SocketTLSContext_enable_early_data(srv_ctx, 16384);  /* Max 16KB early data */

/* Client: Send early data during handshake */
SocketTLS_enable(sock, ctx);
SocketTLS_set_hostname(sock, "example.com");

/* Write early data (before handshake completes) */
size_t written = 0;
int ret = SocketTLS_write_early_data(sock, "GET / HTTP/1.1\r\n\r\n", 18, &written);
if (ret == 1) {
    printf("Sent %zu bytes as early data\n", written);
}

/* Complete handshake */
SocketTLS_handshake_auto(sock);

/* Check if early data was accepted */
SocketTLS_EarlyDataStatus status = SocketTLS_get_early_data_status(sock);
if (status == SOCKET_EARLY_DATA_REJECTED) {
    /* Server rejected - resend via normal I/O */
    SocketTLS_send(sock, "GET / HTTP/1.1\r\n\r\n", 18);
}

/* Server: Read early data during handshake */
unsigned char early_buf[4096];
size_t readbytes = 0;
ret = SocketTLS_read_early_data(srv_sock, early_buf, sizeof(early_buf), &readbytes);

**권장 사용법:**
- 데이터베이스 연결이 시간/일 단위로 열려 있는 경우
- VPN 터널
- 지속적인 WebSocket 연결
- 1시간마다 또는 전송된 데이터 1GB마다 교체

### TLS 성능 최적화```c
#include "tls/SocketTLS.h"
#include "tls/SocketTLSContext.h"

/* TCP handshake optimization - apply before TLS handshake */
SocketTLS_optimize_handshake(sock);  /* Sets TCP_NODELAY + TCP_QUICKACK */

/* After bulk transfer, optionally restore defaults */
SocketTLS_restore_tcp_defaults(sock);  /* Re-enables Nagle */

/* Session cache sharding for multi-threaded servers */
SocketTLSContext_create_sharded_cache(ctx, 
    8,      /* Number of shards (match thread count) */
    1000,   /* Sessions per shard */
    300);   /* Timeout in seconds */

/* Get aggregate statistics from sharded cache */
size_t total_hits, total_misses, total_stores;
SocketTLSContext_get_sharded_stats(ctx, &total_hits, &total_misses, &total_stores);

/* TLS buffer pool for high-connection scenarios */
Arena_T arena = Arena_new();
TLSBufferPool_T pool = TLSBufferPool_new(16384, 100, arena);  /* 16KB buffers, 100 count */

/* Acquire buffer for connection */
void *buf = TLSBufferPool_acquire(pool);
/* ... use buffer for TLS I/O ... */
TLSBufferPool_release(pool, buf);

/* Check pool statistics */
size_t total, in_use, available;
TLSBufferPool_stats(pool, &total, &in_use, &available);

TLSBufferPool_free(&pool);
Arena_dispose(&arena);

/* Get time until next refresh for poll timeout optimization */
int64_t next_ms = SocketTLSContext_crl_next_refresh_ms(ctx);

### 제로카피 파일 전송```c
int file_fd = open("largefile.bin", O_RDONLY);
struct stat st;
fstat(file_fd, &st);

off_t offset = 0;
ssize_t sent = Socket_sendfileall(socket, file_fd, &offset, st.st_size);
close(file_fd);

### 유닉스 도메인 소켓과 FD 전달```c
#include "socket/Socket.h"

/* Stream socket pair for IPC */
Socket_T sock1, sock2;
SocketPair_new(SOCK_STREAM, &sock1, &sock2);

/* Server socket */
Socket_T server = Socket_new(AF_UNIX, SOCK_STREAM, 0);
Socket_bind_unix(server, "/tmp/my.sock");
Socket_listen(server, 10);

/* Client connection */
Socket_T client = Socket_new(AF_UNIX, SOCK_STREAM, 0);
Socket_connect_unix(client, "/tmp/my.sock");

/* Get peer credentials (Linux only) */
int peer_pid = Socket_getpeerpid(accepted);
int peer_uid = Socket_getpeeruid(accepted);
int peer_gid = Socket_getpeergid(accepted);

/* Abstract namespace (Linux only - prefix with @) */
Socket_bind_unix(server, "@abstract-socket");

/* File descriptor passing (SCM_RIGHTS) */
int fd_to_pass = open("/etc/passwd", O_RDONLY);
Socket_sendfd(sock1, fd_to_pass);
close(fd_to_pass);

/* Receive passed FD */
int received_fd;
Socket_recvfd(sock2, &received_fd);
/* received_fd is now a valid FD in this process */
close(received_fd);

/* Multiple FD passing */
int fds[3] = {fd1, fd2, fd3};
Socket_sendfds(sock1, fds, 3);

int received_fds[3];
size_t num_fds;
Socket_recvfds(sock2, received_fds, 3, &num_fds);

### 관찰 가능성 - 로깅```c
#include "core/SocketUtil.h"

/* Custom logging callback */
void my_logger(void *userdata, SocketLogLevel level,
               const char *component, const char *message) {
    printf("[%s] %s: %s\n", SocketLog_levelname(level), component, message);
}
SocketLog_setcallback(my_logger, NULL);

/* Set minimum log level */
SocketLog_setlevel(SOCKET_LOG_DEBUG);

/* Use convenience macros */
#define SOCKET_LOG_COMPONENT "MyApp"
SOCKET_LOG_INFO_MSG("Server started on port %d", port);
SOCKET_LOG_ERROR_MSG("Connection failed: %s", strerror(errno));

/* Correlation IDs for distributed tracing */
SocketLogContext ctx = {0};
strncpy(ctx.request_id, "req-12345", sizeof(ctx.request_id) - 1);
strncpy(ctx.trace_id, "trace-abcde", sizeof(ctx.trace_id) - 1);
SocketLog_setcontext(&ctx);
SOCKET_LOG_INFO_MSG("Processing request");  /* Includes correlation IDs */
SocketLog_clearcontext();

### 소켓별 통계

개별 소켓의 I/O 통계를 추적합니다:```c
#include "socket/Socket.h"

Socket_T sock = Socket_new(AF_INET, SOCK_STREAM, 0);
Socket_connect(sock, "example.com", 80);

/* ... send/recv operations ... */

/* Get per-socket statistics */
SocketStats_T stats;
Socket_getstats(sock, &stats);

printf("Bytes: %zu sent, %zu received\n",
       (size_t)stats.bytes_sent, (size_t)stats.bytes_received);
printf("Packets: %zu sent, %zu received\n",
       (size_t)stats.packets_sent, (size_t)stats.packets_received);
printf("Errors: %zu send, %zu recv\n",
       (size_t)stats.send_errors, (size_t)stats.recv_errors);
printf("Last activity: send=%lld ms, recv=%lld ms ago\n",
       (long long)(Socket_get_monotonic_ms() - stats.last_send_time_ms),
       (long long)(Socket_get_monotonic_ms() - stats.last_recv_time_ms));

/* RTT estimation (Linux only via TCP_INFO) */
if (stats.rtt_us >= 0) {
    printf("RTT: %.2f ms (var: %.2f ms)\n",
           stats.rtt_us / 1000.0, stats.rtt_var_us / 1000.0);
}

/* Reset statistics for next interval */
Socket_resetstats(sock);

Socket_free(&sock);

## 아키텍처

### 모듈 구성```
include/
├── core/          # Foundation layer
│   ├── Arena.h          # Arena memory management
│   ├── Except.h         # Exception handling
│   ├── SocketConfig.h   # Configuration constants
│   ├── SocketCrypto.h   # Cryptographic utilities
│   ├── SocketIPTracker.h # Per-IP connection tracking
│   ├── SocketMetrics.h  # Production metrics (counters, gauges, histograms)
│   ├── SocketRateLimit.h # Token bucket rate limiting
│   ├── SocketRetry.h    # Generic retry with exponential backoff
│   ├── SocketSecurity.h # Security utilities
│   ├── SocketSYNProtect.h # SYN flood protection
│   ├── SocketTimer.h    # Timer management
│   ├── SocketUTF8.h     # UTF-8 validation
│   └── SocketUtil.h     # Logging, error handling, utilities
├── socket/        # Core I/O layer
│   ├── Socket.h         # TCP/Unix domain sockets
│   ├── SocketAsync.h    # Async I/O (io_uring/kqueue)
│   ├── SocketBuf.h      # Circular buffer
│   ├── SocketCommon.h   # Shared socket base
│   ├── SocketDgram.h    # UDP sockets
│   ├── SocketHappyEyeballs.h # RFC 8305 connection racing
│   ├── SocketIO.h       # I/O helpers
│   ├── SocketProxy.h    # HTTP CONNECT/SOCKS proxy
│   ├── SocketReconnect.h # Auto-reconnection
│   └── SocketWS.h       # WebSocket (RFC 6455)
├── dns/           # DNS layer
│   ├── SocketDNS.h      # Async DNS resolution
│   ├── SocketDNSoverTLS.h # DNS-over-TLS (RFC 7858)
│   ├── SocketDNSoverHTTPS.h # DNS-over-HTTPS (RFC 8484)
│   ├── SocketDNSSEC.h   # DNSSEC validation (RFC 4033-4035)
│   ├── SocketDNSCookie.h # DNS cookies (RFC 7873)
│   ├── SocketDNSResolver.h # High-level resolver API
│   ├── SocketDNSWire.h  # Wire format encoding/decoding
│   ├── SocketDNSTransport.h # UDP/TCP transport layer
│   ├── SocketDNSNegCache.h # Negative response caching
│   └── SocketDNSError.h # Extended DNS errors (RFC 8914)
├── poll/          # Event system
│   └── SocketPoll.h     # Cross-platform polling
├── pool/          # Connection management
│   └── SocketPool.h     # Connection pooling
├── tls/           # Security layer
│   ├── SocketTLS.h      # TLS operations
│   ├── SocketTLSContext.h # TLS context management
│   ├── SocketTLSConfig.h # TLS configuration constants
│   ├── SocketDTLS.h     # DTLS operations
│   ├── SocketDTLSContext.h # DTLS context management
│   └── SocketDTLSConfig.h # DTLS configuration constants
├── http/          # HTTP protocol stack
│   ├── SocketHTTP.h     # HTTP core (RFC 9110)
│   ├── SocketHTTP1.h    # HTTP/1.1 (RFC 9112)
│   ├── SocketHPACK.h    # HPACK (RFC 7541)
│   ├── SocketHTTP2.h    # HTTP/2 (RFC 9113)
│   ├── SocketHTTPClient.h # HTTP client API
│   └── SocketHTTPServer.h # HTTP server API
├── quic/          # QUIC transport layer
│   ├── SocketQUICConnection.h # Connection management (RFC 9000)
│   ├── SocketQUICStream.h   # Stream multiplexing
│   ├── SocketQUICPacket.h   # Packet parsing/serialization
│   ├── SocketQUICFrame.h    # Frame encoding/decoding
│   ├── SocketQUICHandshake.h # TLS 1.3 handshake integration
│   ├── SocketQUICFlow.h     # Flow control
│   ├── SocketQUICLoss.h     # Loss detection (RFC 9002)
│   ├── SocketQUICMigration.h # Path migration
│   └── SocketQUICVersion.h  # Version negotiation
└── simple/        # Return-code based convenience API
    ├── SocketSimple.h       # Core simple socket API
    ├── SocketSimple-http.h  # Simple HTTP client
    ├── SocketSimple-tls.h   # Simple TLS connections
    ├── SocketSimple-ws.h    # Simple WebSocket
    └── SocketSimple-dns.h   # Simple DNS resolution

### 우아한 종료

이 라이브러리는 시그널 핸들러를 **설치하지 않습니다**. 애플리케이션은 종료 시그널을 직접 처리해야 합니다. 권장 패턴은 self-pipe 트릭을 사용하는 것입니다:```c
#include <signal.h>
#include <unistd.h>

static int signal_pipe[2];

/* Async-signal-safe handler - only writes to pipe */
static void shutdown_handler(int signo) {
    (void)signo;
    char byte = 1;
    (void)write(signal_pipe[1], &byte, 1);  /* write() is async-signal-safe */
}

int main(void) {
    pipe(signal_pipe);
    fcntl(signal_pipe[0], F_SETFL, O_NONBLOCK);
    fcntl(signal_pipe[1], F_SETFL, O_NONBLOCK);
    
    struct sigaction sa = {0};
    sa.sa_handler = shutdown_handler;
    sigemptyset(&sa.sa_mask);
    sigaction(SIGINT, &sa, NULL);
    sigaction(SIGTERM, &sa, NULL);
    
    /* Add signal pipe to poll set */
    SocketPoll_add_fd(poll, signal_pipe[0], POLL_READ, NULL);
    
    /* In event loop, check for signal pipe readability */
    /* Then use SocketPool_drain() for graceful connection draining */
}

### 빌드 옵션

| 옵션 | 설명 | 기본값 |
|--------|-------------|---------|
| `CMAKE_BUILD_TYPE` | 디버그 또는 릴리스 | Debug |
| `ENABLE_TLS` | TLS/DTLS 지원 활성화 | ON (auto-detect) |
| `ENABLE_HTTP_COMPRESSION` | gzip/deflate/brotli 압축 활성화 | OFF |
| `ENABLE_SANITIZERS` | ASan + UBSan 활성화 | OFF |
| `ENABLE_ASAN` | AddressSanitizer만 활성화 | OFF |
| `ENABLE_UBSAN` | UndefinedBehaviorSanitizer만 활성화 | OFF |
| `ENABLE_COVERAGE` | gcov 커버리지 활성화 | OFF |
| `ENABLE_FUZZING` | 퍼즈 테스트 활성화 (Clang 필요) | OFF |

### 폴 백엔드 선택

폴 백엔드는 플랫폼에 따라 자동으로 선택됩니다:
- **Linux** - epoll (Linux에서 가장 빠름)
- **BSD/macOS** - kqueue
- **기타 POSIX** - poll(2) 대체

### 비동기 I/O 백엔드 선택

- **Linux 5.1+** - io_uring (진정한 비동기)
- **BSD/macOS** - kqueue AIO
- **대체** - 엣지 트리거 폴링

## 테스트 및 품질

### 테스트 스위트

라이브러리는 `src/test/` 디렉토리에 포괄적인 테스트를 포함합니다:

| 카테고리 | 테스트 파일 |
|----------|------------|
| 코어 | `test_arena.c`, `test_except.c`, `test_crypto.c`, `test_utf8.c`, `test_ratelimit.c` |
| 소켓 | `test_socket.c`, `test_socketdgram.c`, `test_socketbuf.c` |
| 네트워킹 | `test_socketpoll.c`, `test_socketpool.c`, `test_socketdns.c`, `test_socketerror.c` |
| 연결 | `test_happy_eyeballs.c`, `test_reconnect.c`, `test_proxy.c`, `test_proxy_integration.c` |
| HTTP | `test_http_core.c`, `test_http1_parser.c`, `test_hpack.c`, `test_http2.c`, `test_http_client.c`, `test_http_integration.c`, `test_http2_integration.c` |
| WebSocket | `test_websocket.c`, `test_ws_integration.c` |
| TLS/DTLS | `test_tls_integration.c`, `test_tls_phase4.c`, `test_tls_pinning.c`, `test_tls_crl.c`, `test_tls_ct.c`, `test_dtls_integration.c`, `test_dtls_cookie.c` |
| 보안 | `test_synprotect.c`, `test_security.c`, `test_signals.c` |
| 통합 | `test_integration.c`, `test_async.c`, `test_threadsafety.c`, `test_coverage.c` |

### 퍼즈 테스트

`src/fuzz/` 디렉토리에 130개 이상의 퍼즈 하니스가 있으며, 다음을 포함합니다:
- HTTP/1.1 파서 및 요청 스머글링 방지
- HTTP/2 프레임 파싱 및 HPACK 인코딩
- WebSocket 프레이밍 및 permessage-deflate
- URI 파싱 및 검증
- UTF-8 검증
- TLS/DTLS 핸드셰이크 및 I/O 작업
- TLS 세션 티켓, ALPN, SNI, CRL 관리
- DTLS 쿠키 생성 및 검증
- 인증서 핀닝 및 파싱
- 경로 검증 및 보안 점검```bash
# Build with fuzzing
cmake -S . -B build -DENABLE_FUZZING=ON -DCMAKE_C_COMPILER=clang
cmake --build build

### 지속적 통합

GitHub Actions 파이프라인 (`.github/workflows/ci.yml`):

| 작업 | 플랫폼 | 설명 |
|-----|----------|-------------|
| `build` | Ubuntu | 디버그 및 릴리스 빌드 |
| `sanitizers` | Ubuntu | ASan, UBSan, 결합 |
| `valgrind` | Ubuntu | 메모리 누수 검사 |
| `macos` | macOS | kqueue 백엔드 테스트 |
| `macos-sanitizers` | macOS | 크로스 플랫폼 sanitizer |
| `coverage` | Ubuntu | lcov를 사용한 코드 커버리지 |
| `static-analysis` | Ubuntu | cppcheck + clang-tidy |

## 예외 유형

### 핵심 예외
- `Socket_Failed` - 일반적인 소켓 작업 실패
- `Socket_Closed` - 피어에 의해 연결 종료됨
- `SocketUnix_Failed` - 유닉스 소켓 작업 실패
- `SocketDgram_Failed` - UDP 소켓 작업 실패
- `SocketPoll_Failed` - 이벤트 폴링 실패
- `SocketPool_Failed` - 연결 풀 작업 실패
- `SocketDNS_Failed` - DNS 해석 실패
- `SocketTimer_Failed` - 타이머 작업 실패
- `SocketRateLimit_Failed` - 속도 제한기 실패
- `SocketRetry_Failed` - 재시도 작업 실패
- `SocketAsync_Failed` - 비동기 I/O 실패
- `SocketCrypto_Failed` - 암호화 작업 실패

### 연결 예외
- `SocketHE_Failed` - Happy Eyeballs 연결 실패
- `SocketReconnect_Failed` - 재연결 작업 실패
- `SocketProxy_Failed` - 프록시 연결 실패

### TLS/DTLS 예외
- `SocketTLS_Failed` - 일반적인 TLS 작업 실패
- `SocketTLS_HandshakeFailed` - TLS 핸드셰이크 실패
- `SocketTLS_VerifyFailed` - 인증서 검증 실패
- `SocketTLS_ProtocolError` - TLS 프로토콜 오류
- `SocketTLS_ShutdownFailed` - TLS 종료 실패
- `SocketTLS_PinVerifyFailed` - 인증서 고정 검증 실패
- `SocketDTLS_Failed` - 일반적인 DTLS 작업 실패
- `SocketDTLS_HandshakeFailed` - DTLS 핸드셰이크 실패
- `SocketDTLS_VerifyFailed` - DTLS 인증서 검증 실패
- `SocketDTLS_CookieFailed` - DTLS 쿠키 교환 실패
- `SocketDTLS_TimeoutExpired` - DTLS 핸드셰이크 시간 초과
- `SocketDTLS_ShutdownFailed` - DTLS 종료 실패

### HTTP 예외
- `SocketHTTP_ParseError` - HTTP 파싱 오류
- `SocketHTTP_InvalidURI` - 잘못된 URI
- `SocketHTTP_InvalidHeader` - 잘못된 헤더
- `SocketHTTP1_ParseError` - HTTP/1.1 파싱 오류
- `SocketHPACK_Failed` - HPACK 압축 오류
- `SocketHTTP2_ProtocolError` - HTTP/2 프로토콜 오류
- `SocketHTTP2_StreamError` - HTTP/2 스트림 오류
- `SocketHTTP2_FlowControlError` - HTTP/2 흐름 제어 오류
- `SocketHTTPClient_Failed` - HTTP 클라이언트 실패
- `SocketHTTPClient_Timeout` - HTTP 클라이언트 시간 초과
- `SocketHTTPClient_TLSFailed` - HTTP 클라이언트 TLS 오류
- `SocketHTTPClient_DNSFailed` - HTTP 클라이언트 DNS 실패
- `SocketHTTPClient_ConnectFailed` - HTTP 클라이언트 연결 실패
- `SocketHTTPClient_ProtocolError` - HTTP 클라이언트 프로토콜 오류
- `SocketHTTPClient_TooManyRedirects` - 너무 많은 리디렉션
- `SocketHTTPClient_ResponseTooLarge` - 응답 크기 제한 초과
- `SocketHTTPServer_Failed` - HTTP 서버 실패

### WebSocket 예외
- `SocketWS_Failed` - WebSocket 작업 실패
- `SocketWS_ProtocolError` - WebSocket 프로토콜 오류
- `SocketWS_Closed` - WebSocket 연결 종료

### 보안 예외
- `SocketSYNProtect_Failed` - SYN 보호 실패

## 라이선스

사용 상세는 `LICENSE`를 참조하십시오.