http.go
func (req *Request) RequestURI() []byte {
	if req.parsedURI {
		requestURI := req.uri.RequestURI()
		req.SetRequestURIBytes(requestURI)
	}
	return req.Header.RequestURI()
}
func (req *Request) RequestURI() []byte {
	if req.parsedURI {
		requestURI := req.uri.RequestURI()
		req.SetRequestURIBytes(requestURI)
	}
	return req.Header.RequestURI()
}
// RequestURI returns request's URI.