CURLOPT_BUFFERSIZE allows an application to set a prefered buffer size

for receiving data from the network. It is meant as a hint, not as a forced
limit.

lib/url.c

@@ -1011,6 +1011,19 @@ CURLcode Curl_setopt(struct SessionHandle *data, CURLoption option, ...)
      */
     data->set.telnet_options = va_arg(param, struct curl_slist *);
     break;
+
+  case CURLOPT_BUFFERSIZE:
+    /*
+     * The application kindly asks for a differently sized receive buffer.
+     * If it seems reasonable, we'll use it.
+     */
+    data->set.buffer_size = va_arg(param, long);
+
+    if(data->set.buffer_size> (BUFSIZE -1 ))
+      data->set.buffer_size = 0; /* huge internal default */
+
+    break;
+
   default:
     /* unknown tag and its companion, just ignore: */
     return CURLE_FAILED_INIT; /* correct this */