Update networking layer w/ CURL and emscripten impl

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

@@ -0,0 +1,82 @@
+---
+c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
+SPDX-License-Identifier: curl
+Title: CURLOPT_XFERINFODATA
+Section: 3
+Source: libcurl
+See-also:
+  - CURLOPT_NOPROGRESS (3)
+  - CURLOPT_VERBOSE (3)
+  - CURLOPT_XFERINFOFUNCTION (3)
+Protocol:
+  - All
+Added-in: 7.32.0
+---
+
+# NAME
+
+CURLOPT_XFERINFODATA - pointer passed to the progress callback
+
+# SYNOPSIS
+
+~~~c
+#include <curl/curl.h>
+
+CURLcode curl_easy_setopt(CURL *handle, CURLOPT_XFERINFODATA, void *pointer);
+~~~
+
+# DESCRIPTION
+
+Pass a *pointer* that is untouched by libcurl and passed as the first
+argument in the progress callback set with CURLOPT_XFERINFOFUNCTION(3).
+
+This is an alias for CURLOPT_PROGRESSDATA(3).
+
+# DEFAULT
+
+NULL
+
+# %PROTOCOLS%
+
+# EXAMPLE
+
+~~~c
+struct progress {
+  char *private;
+  size_t size;
+};
+
+static int progress_cb(void *clientp,
+                       curl_off_t dltotal,
+                       curl_off_t dlnow,
+                       curl_off_t ultotal,
+                       curl_off_t ulnow)
+{
+  struct progress *memory = clientp;
+  printf("private ptr: %p\n", memory->private);
+  /* use the values */
+
+  return 0; /* all is good */
+}
+
+int main(void)
+{
+  CURL *curl = curl_easy_init();
+  if(curl) {
+    struct progress data;
+
+    /* pass struct to callback  */
+    curl_easy_setopt(curl, CURLOPT_XFERINFODATA, &data);
+    curl_easy_setopt(curl, CURLOPT_XFERINFOFUNCTION, progress_cb);
+  }
+}
+~~~
+
+# %AVAILABILITY%
+
+# RETURN VALUE
+
+curl_easy_setopt(3) returns a CURLcode indicating success or error.
+
+CURLE_OK (0) means everything was OK, non-zero means an error occurred, see
+libcurl-errors(3).