Please see the FAQ in our main README.md before submitting your issue.

What problem is the feature used to solve?

Go added a new feature called NewResponseController in go 1.20. Pay attention to the doc blow:

The ResponseWriter should be the original value passed to the [Handler.ServeHTTP] method, or have an Unwrap method returning the original ResponseWriter.

As it said, custom ResponseWriter should add an Unwrap method to return underlaying ResponseWriter.

Currently, there is a custom ResponseWriter in transport/http. And it is used in http.Context:

Shall we support this feature, so that we can use some code likes below:

_ = http.NewServer(
	http.ResponseEncoder(func(w http.ResponseWriter, r *http.Request, i any) error {
		rc := nt.NewResponseController(w)
		bs, _ := encoding.GetCodec("json").Marshal(i)

		n := len(bs) / 2

		n, _ = w.Write(bs[:n])    // 1. write half of the response
		_ = rc.Flush()            // 2. flush response first
		_, err := w.Write(bs[n:]) // 3. write the rest
		return err
	}),
)

Requirements description of the feature

Add an "Unwrap" method to transport/http.responseWriter.

func (w *responseWriter) Unwrap() http.ResponseWriter { return w.w }

References

• go doc NewResponseController