Receiver "kind" not known until calling receiver.receive()

[aboba]

In Edge ORC, we got feedback from developers who attempted to hook up a receiver to an audio or video tag prior to calling receiver.receive(). Since the "kind" of a receiver was not determined until receiver.receive() is called, we were throwing an exception, and developers found this to be annoying.

To fix this, in Edge we added "kind" to the constructor. This would look like the following:

[ Constructor (RTCDtlsTransport transport, optional RTCDtlsTransport rtcpTransport, optional DOMString kind)]
partial interface RTCRtpReceiver : RTCStatsProvider {
};

[ibc]

I agree.

[robin-raymond]

+1 I'm in favour if this means a MediaStreamTrack is available immediately after construction.

I found it a bit awkward to not be able to have a MediaStreamTrack to wire up immediately without having to wait for some kind of signalling from the remote party to call receive().