code: func NewEchoServer(addr string) *EchoServer {
  	return &EchoServer{
  		addr: addr,
  		server: goetty.NewServer(addr,
  			goetty.WithServerDecoder(goetty.NewIntLengthFieldBasedDecoder(&StringDecoder{})),
  			goetty.WithServerEncoder(&StringEncoder{})),
  	}
  }
docs: // NewEchoServer create new server