If the remote side calls stop() on the SctpTransport the local SctpTransport will be closed. How does the developer know this has happened?
If the remote SctpTransport is closed, RTCDataChannelState will transition to "closed" and the RTCDataChannel "onclosed" event handler will fire.
What happens if an RTCDataChannel has not been constructed yet and sctpTransport.stop() is called? In that case, we will indeed need SctpTransport.state and a state change event. Ugh.
SctpTransport state and state change event
Fix for Issue #403