Additional ICE metrics for pacing STUN packets

[vr000m]

Assuming that there will be a pacing limits on the STUN packets. We would need:

• global pacing limit in Kbps?
• defaultTa vs chosenTa
• droppedIceChecksBeforeSend
• totalNumIceAgents

[vr000m]

@aboba do you have thoughts on this. It was based on my notes from the Berlin IETF.

[vr000m]

TPAC16 decision: hold until we know more, based on IETF guidance.