server: remove useless code

serversession.go

@@ -176,7 +176,6 @@ type ServerSession struct {
 	announcedTracks     []ServerSessionAnnouncedTrack // publish
 	udpLastFrameTime    *int64                        // publish
 	udpCheckStreamTimer *time.Timer
-	udpReceiverReportTimer *time.Timer
 	writerRunning       bool
 	writeBuffer         *ringbuffer.RingBuffer
 
@@ -205,7 +204,6 @@ func newServerSession(
 		conns:               make(map[*ServerConn]struct{}),
 		lastRequestTime:     time.Now(),
 		udpCheckStreamTimer: emptyTimer(),
-		udpReceiverReportTimer: emptyTimer(),
 		request:             make(chan sessionRequestReq),
 		connRemove:          make(chan *ServerConn),
 		startWriter:         make(chan struct{}),
@@ -1068,13 +1066,15 @@ func (ss *ServerSession) handleRequest(sc *ServerConn, req *base.Request) (*base
 			ss.setuppedStream.readerSetInactive(ss)
 
 			ss.state = ServerSessionStatePrePlay
-			ss.udpCheckStreamTimer = emptyTimer()
 
 			switch *ss.setuppedTransport {
 			case TransportUDP:
+				ss.udpCheckStreamTimer = emptyTimer()
+
 				ss.s.udpRTCPListener.removeClient(ss)
 
 			case TransportUDPMulticast:
+				ss.udpCheckStreamTimer = emptyTimer()
 
 			default: // TCP
 				ss.tcpConn.readFunc = ss.tcpConn.readFuncStandard
@@ -1085,11 +1085,11 @@ func (ss *ServerSession) handleRequest(sc *ServerConn, req *base.Request) (*base
 
 		case ServerSessionStateRecord:
 			ss.state = ServerSessionStatePreRecord
-			ss.udpCheckStreamTimer = emptyTimer()
-			ss.udpReceiverReportTimer = emptyTimer()
 
 			switch *ss.setuppedTransport {
 			case TransportUDP:
+				ss.udpCheckStreamTimer = emptyTimer()
+
 				ss.s.udpRTPListener.removeClient(ss)
 				ss.s.udpRTCPListener.removeClient(ss)
 
@@ -1098,8 +1098,6 @@ func (ss *ServerSession) handleRequest(sc *ServerConn, req *base.Request) (*base
 					ss.announcedTracks[trackID].rtcpReceiver = nil
 				}
 
-			case TransportUDPMulticast:
-
 			default: // TCP
 				ss.tcpConn.readFunc = ss.tcpConn.readFuncStandard
 				err = errSwitchReadFunc