Add latency metrics to sip pings

[atibdialpad]

Can we add latency measurement. Would be great to have loss info alongside latency. Shd be as simple as recording start and stop time between socket send and recv. Ref: https://github.com/laurieodgers/sipping/blob/f1fc789989faf2436f0e4f0499b5fe36527b43a1/sipping.py#L95