message: fixed http_client_coro bugs.
diff: @@ -156,6 +156,18 @@ static int http_client_coro_execute(zval *zobject, char *uri, zend_size_t uri_le
  swoole_php_fatal_error(E_ERROR, "[1] swString_new(%d) failed.", SW_HTTP_RESPONSE_INIT_SIZE);
  return SW_ERR;
  }
  + http->header_field_buffer = swString_new(SW_HTTP_HEADER_BUFFER_SIZE);
  + if (http->header_field_buffer == NULL)
  + {
  + swoole_php_fatal_error(E_ERROR, "[2] swString_new(%d) failed.", SW_HTTP_HEADER_BUFFER_SIZE);
  + return SW_ERR;
  + }
  + http->header_value_buffer = swString_new(SW_HTTP_HEADER_BUFFER_SIZE);
  + if (http->header_value_buffer == NULL)
  + {
  + swoole_php_fatal_error(E_ERROR, "[3] swString_new(%d) failed.", SW_HTTP_HEADER_BUFFER_SIZE);
  + return SW_ERR;
  + }
  }
  else
  {
  