Zend\Diactoros\ServerRequest::withParsedBody PHP Method

    public function withParsedBody($data)
    {
        $new = clone $this;
        $new->parsedBody = $data;
        return $new;
    }

 /**
  * @param UriInterface $uri
  * @param string       $method
  * @param array        $data
  * @param array        $query
  * @param array        $cookies
  * @param array        $headers
  * @return ServerRequest
  */
 protected function request(UriInterface $uri, $method, array $data = [], array $query = [], array $cookies = [], array $headers = [])
 {
     $request = new ServerRequest([], [], $uri, $method, 'php://temp', $headers);
     return $request->withParsedBody($data)->withQueryParams($query)->withCookieParams($cookies);
 }