// 1: Echo
	h1 := NewSingleHandler[*testRequest, *testResponse](handlerTest, func() *testRequest {
		return &testRequest{}
	}, func() *testResponse {
		return &testResponse{}
	})
	// Handles incoming requests, returns a response
	handler1 := func(req *testRequest) (resp *testResponse, err *RemoteErr) {
		resp = h1.NewResponse()
		*resp = testResponse{
			OrgNum:    req.Num,
			OrgString: req.String,

			defer PutByteBuffer(payload)
			return append(GetByteBuffer()[:0], payload...), nil
		}))
		errFatal(rpc.Register(remote, func(req *testRequest) (resp *testResponse, err *RemoteErr) {
			return &testResponse{
				OrgNum:    req.Num,
				OrgString: req.String,
				Embedded:  *req,
			}, nil
		}))
		errFatal(err)
	}
	const payloadSize = 512