Instrumenting the plugs with the expansion was very helpful, thanks again.
We can now see that the very high latency appears to be occurring in Plug.Parsers. We saw a few that were extremely slow (8s, 30s) vs the usual ~200us. Plugs before it & after it are very fast, as are other post requests of the same type before & after.
I added more detail on another post where someone else may be having the same problem:
Attempts to reproduce haven’t been successful yet. Any additional thoughts?
