switch string(hdr[:]) {
	case "GET /", "HEAD ", "POST ", "PUT /", "OPTIO":
		return true
	}
	return false
}

// MaxBytesHandler returns a [Handler] that runs h with its [ResponseWriter] and [Request.Body] wrapped by a MaxBytesReader.
func MaxBytesHandler(h Handler, n int64) Handler {
	return HandlerFunc(func(w ResponseWriter, r *Request) {
		r2 := *r
		r2.Body = MaxBytesReader(w, r.Body, n)

		)
		echo := HandlerFunc(func(w ResponseWriter, r *Request) {
			var buf bytes.Buffer
			handlerN, handlerErr = io.Copy(&buf, r.Body)
			io.Copy(w, &buf)
		})

		cst := newClientServerTest(t, mode, MaxBytesHandler(echo, maxSize))
		// We need to close cst explicitly here so that in-flight server
		// requests don't race with the call to SetRSTAvoidanceDelay for a retry.
		defer cst.close()
		ts := cst.ts