1 // Copyright 2017 The Prometheus Authors
2 // Licensed under the Apache License, Version 2.0 (the "License");
3 // you may not use this file except in compliance with the License.
4 // You may obtain a copy of the License at
6 // http://www.apache.org/licenses/LICENSE-2.0
8 // Unless required by applicable law or agreed to in writing, software
9 // distributed under the License is distributed on an "AS IS" BASIS,
10 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11 // See the License for the specific language governing permissions and
12 // limitations under the License.
23 func newDelegator(w http.ResponseWriter, observeWriteHeaderFunc func(int)) delegator {
24 d := &responseWriterDelegator{
26 observeWriteHeader: observeWriteHeaderFunc,
30 if _, ok := w.(http.CloseNotifier); ok {
33 if _, ok := w.(http.Flusher); ok {
36 if _, ok := w.(http.Hijacker); ok {
39 if _, ok := w.(io.ReaderFrom); ok {
43 return pickDelegator[id](d)