Update networking layer w/ CURL and emscripten impl

External/curl-8.17.0/docs/libcurl/opts/CURLOPT_SOCKOPTDATA.md

@@ -0,0 +1,74 @@
+---
+c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
+SPDX-License-Identifier: curl
+Title: CURLOPT_SOCKOPTDATA
+Section: 3
+Source: libcurl
+See-also:
+  - CURLOPT_OPENSOCKETFUNCTION (3)
+  - CURLOPT_SOCKOPTFUNCTION (3)
+Protocol:
+  - All
+Added-in: 7.16.0
+---
+
+# NAME
+
+CURLOPT_SOCKOPTDATA - pointer to pass to sockopt callback
+
+# SYNOPSIS
+
+~~~c
+#include <curl/curl.h>
+
+CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SOCKOPTDATA, void *pointer);
+~~~
+
+# DESCRIPTION
+
+Pass a *pointer* that is untouched by libcurl and passed as the first
+argument in the sockopt callback set with CURLOPT_SOCKOPTFUNCTION(3).
+
+# DEFAULT
+
+NULL
+
+# %PROTOCOLS%
+
+# EXAMPLE
+
+~~~c
+static int sockopt_callback(void *clientp, curl_socket_t curlfd,
+                            curlsocktype purpose)
+{
+  int val = *(int *)clientp;
+  setsockopt((int)curlfd, SOL_SOCKET, SO_RCVBUF,
+             (const char *)&val, sizeof(val));
+  return CURL_SOCKOPT_OK;
+}
+
+int main(void)
+{
+  CURL *curl = curl_easy_init();
+  if(curl) {
+    CURLcode res;
+    int recvbuffersize = 256 * 1024;
+
+    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
+
+    /* call this function to set options for the socket */
+    curl_easy_setopt(curl, CURLOPT_SOCKOPTFUNCTION, sockopt_callback);
+    curl_easy_setopt(curl, CURLOPT_SOCKOPTDATA, &recvbuffersize);
+
+    res = curl_easy_perform(curl);
+
+    curl_easy_cleanup(curl);
+  }
+}
+~~~
+
+# %AVAILABILITY%
+
+# RETURN VALUE
+
+Returns *CURLE_OK* if the option is supported, and *CURLE_UNKNOWN_OPTION* if not.