add Remove listener method on cmux

cmux.go

@@ -103,6 +103,8 @@ type CMux interface {
 	HandleError(ErrorHandler)
 	// sets a timeout for the read of matchers
 	SetReadTimeout(time.Duration)
+
+	Remove(l net.Listener) error
 }
 
 type matchersListener struct {
@@ -216,6 +218,34 @@ func (m *cMux) Close() {
 	m.closeDoneChans()
 }
 
+func (m *cMux) Remove(l net.Listener) error {
+
+	if l == nil {
+		return errors.New("mux: nil listener")
+	}
+	if l == m.root {
+		return errors.New("mux: cannot remove root listener")
+	}
+	cl, ok := l.(muxListener)
+	if !ok {
+		return fmt.Errorf("mux: listener %v is not a mux listener", l)
+	}
+
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	for i, sl := range m.sls {
+		if sl.l.Listener == l {
+
+			cl.donec <- struct{}{}
+			m.sls = append(m.sls[:i], m.sls[i+1:]...)
+			return nil
+		}
+	}
+
+	return fmt.Errorf("mux: listener %v not found", l)
+}
+
 func (m *cMux) closeDoneChans() {
 	m.mu.Lock()
 	defer m.mu.Unlock()