记录 response.Body.Close() 引发的 goroutine 泄漏

response, err = http.Do(req)if err != nil{  logging.Err()	return}defer response.Body.Close()

type bodyEOFSignal struct {	body         io.ReadCloser	mu           sync.Mutex        // guards following 4 fields	closed       bool              // whether Close has been called	rerr         error             // sticky Read error	fn           func(error) error // err will be nil on Read io.EOF	earlyCloseFn func() error      // optional alt Close func used if io.EOF not seen}// /usr/local/Cellar/go@1.13/1.13.11/libexec/src/net/http/transport.go:2594func (es *bodyEOFSignal) Close() error {	es.mu.Lock()	defer es.mu.Unlock()	if es.closed { //重复关也没事～		return nil	}	es.closed = true //设置已经关闭	if es.earlyCloseFn != nil && es.rerr != io.EOF {		return es.earlyCloseFn()	}	err := es.body.Close()	return es.condfn(err)}

func (t *Transport) roundTrip(req *Request) (*Response, error) {	//省略一堆代码	for {		select {		case <-ctx.Done():			req.closeBody()			return nil, ctx.Err()		default:		}
		// Get the cached or newly-created connection to either the		// host (for http or https), the http proxy, or the http proxy		// pre-CONNECTed to https server. In any case, we'll be ready		// to send it requests.		pconn, err := t.getConn(treq, cm)		if err != nil {			t.setReqCanceler(req, nil)			req.closeBody()			return nil, err		}}// /usr/local/Cellar/go@1.13/1.13.11/libexec/src/net/http/transport.go:1580// t.getConn（）func (t *Transport) dialConn(ctx context.Context, cm connectMethod) (pconn *persistConn, err error) {	pconn = &persistConn{		t:             t,		cacheKey:      cm.key(),		reqch:         make(chan requestAndChan, 1),		writech:       make(chan writeRequest, 1),		closech:       make(chan struct{}),		writeErrCh:    make(chan error, 1),		writeLoopDone: make(chan struct{}),	}	//省略一堆代码	go pconn.readLoop()	go pconn.writeLoop()	return pconn, nil}  

func (pc *persistConn) readLoop() {		waitForBodyRead := make(chan bool, 2)    //我们一开始要的构造body对象以及close调用的两个方法		body := &bodyEOFSignal{			body: resp.Body,			earlyCloseFn: func() error {				waitForBodyRead <- false				<-eofc // will be closed by deferred call at the end of the function				return nil			},			fn: func(err error) error {				isEOF := err == io.EOF				waitForBodyRead <- isEOF				if isEOF {					<-eofc // see comment above eofc declaration				} else if err != nil {					if cerr := pc.canceled(); cerr != nil {						return cerr					}				}				return err			},		}
		resp.Body = body				select {		case rc.ch <- responseAndError{res: resp}:		case <-rc.callerGone:			return		}
		// Before looping back to the top of this function and peeking on		// the bufio.Reader, wait for the caller goroutine to finish		// reading the response body. (or for cancellation or death)		select {    //接收earlyCloseFn传过来的false，也就是这里没有close，goroutine卡在这里了，造成了泄漏		case bodyEOF := <-waitForBodyRead:			pc.t.setReqCanceler(rc.req, nil) // before pc might return to idle pool			alive = alive &&				bodyEOF &&				!pc.sawEOF &&				pc.wroteRequest() &&				tryPutIdleConn(trace)			if bodyEOF {				eofc <- struct{}{}			}		case <-rc.req.Cancel:			alive = false			pc.t.CancelRequest(rc.req)		case <-rc.req.Context().Done():			alive = false			pc.t.cancelRequest(rc.req, rc.req.Context().Err())		case <-pc.closech:			alive = false		}	}}