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.