[webrtc-stats] statistics for BWE probes? (#522)

fippo has just created a new issue for https://github.com/w3c/webrtc-stats:

== statistics for BWE probes? ==
webrtc.org uses either all-padding packets (when RTX is not negotiated) or RTX packets as a way to probe the bandwidth. Prior to Chrome fixing [this issue](https://bugs.chromium.org/p/webrtc/issues/detail?id=10525) at least the padding variant of this was quite visible in the statistics.
 
https://w3c.github.io/webrtc-stats/#dom-rtcinboundrtpstreamstats-headerbytesreceived
is less ideal for this since this includes a linear component (the rtp header) and a burst-y one (the padding probes).
I'm not sure how this would work for RTX.

Can/should we have something like bandwidthProbeCount and bandwidthProbeBytesSent / Received?

Please view or discuss this issue at https://github.com/w3c/webrtc-stats/issues/522 using your GitHub account