public void PlayStream(string name,ulong flowId,uint streamId, OutFileRTMPFLVStream flvStream)
{
if (_flvStream != null) return;
var flowStream = new FlowWriter(FlowStream.Signature + (char)streamId,this, flowId);
flowStream.Play(name);
_flvStream = flvStream;
_flvStream.SignalAttachedToInStream();
}