The current ratelimiting code has a number of flaws:
- the ratelimit is statically defined, instead of being modifiable by the NRM daemon
- the phase context reports have their own logic that ignores/bypass the rate limiting and could cause issues
the phase context reports don't take into account blocking sends, the say
masterdoes it with progress reports.
We should merge the concepts of NRM_RATELIMIT_THRESOLD and NRM_DAMPER, and have
downstream_api.c handle both of those the same way: taking into account blocking sends, and aggregating info into the context.