code: public boolean isAvailable() {
  		boolean available = this.rtpChannel.isAvailable();
  		if (!this.rtcpMux) {
  			available = available && this.rtcpChannel.isAvailable();
  		}
  		return available;
  	}
docs: Indicates whether the channel is available (ready to use).
  
  For regular SIP calls, the channel should be available as soon as it is
  activated.<br>
  But for WebRTC calls the channel will only become available as soon as
  the DTLS handshake completes.
  
  @return Returns true if the channel is available. Returns false otherwise.