RTCAudioSourceStats: type property

The RTCAudioSourceStats dictionary's property type is a string with value media-source.

The type of media-source identifies the type of statistics as either RTCAudioSourceStats or RTCVideoSourceStats when iterating the RTCStatsReport returned by RTCRtpSender.getStats() or RTCPeerConnection.getStats(). The type of stats can further be differentiated using the kind, which will be audio for RTCAudioSourceStats.