Provide CIRC_BW and STREAM event fields for congestion control
In tpo/network-health/sbws#40125 (closed), it looks like sbws is going to need some way to know when congestion control exited slow start, so it can begin measurement.
I can create a field in CIRC_BW that says SS=0 or 1 that it can look at for this purpose. I might as well also add CWND, RTT, and MIN_RTT fields, for diagnostics.
I will also add STREAM status fields, to signify XON/XOFF, as this will help sbws monitor for slow bandwidth authority webservers.
Edited by Mike Perry