code: public function handle($conn, \React\EventLoop\LoopInterface $loop)
      {
          sleep(1);
          var_dump(getmypid() . ":" . fread($conn, 1024));
          fwrite($conn, "HTTP/1.1 200 OK
  Server: GitHub.com
  Date: Fri, 01 Jul 2016 03:38:21 GMT
  Content-Type: text/html; charset=utf-8\r\n\r\n");
      }
docs: handle request
  
  @param $conn
  @param \React\EventLoop\LoopInterface $loop
  @return mixed