}

func (w *http2responseWriter) Header() Header {
	rws := w.rws
	if rws == nil {
		panic("Header called after Handler finished")
	}
	if rws.handlerHeader == nil {
		rws.handlerHeader = make(Header)
	}
	return rws.handlerHeader
}

// checkWriteHeaderCode is a copy of net/http's checkWriteHeaderCode.
func http2checkWriteHeaderCode(code int) {