/*
 * call-seq:
 *   Curl::Easy.http_post(url, "some=urlencoded%20form%20data&and=so%20on") => true
 *   Curl::Easy.http_post(url, "some=urlencoded%20form%20data", "and=so%20on", ...) => true
 *   Curl::Easy.http_post(url, "some=urlencoded%20form%20data", Curl::PostField, "and=so%20on", ...) => true
 *   Curl::Easy.http_post(url, Curl::PostField, Curl::PostField ..., Curl::PostField) => true
 *
 * POST the specified formdata to the currently configured URL using
 * the current options set for this Curl::Easy instance. This method
 * always returns true, or raises an exception (defined under
 * Curl::Err) on error.
 *
 * If you wish to use multipart form encoding, you'll need to supply a block
 * in order to set multipart_form_post true. See #http_post for more
 * information.
 */
static VALUE ruby_curl_easy_class_perform_post(int argc, VALUE *argv, VALUE klass) {