Adds ProfileEvent when Keeper rejects a write

Why it matters

This feature provides enhanced observability by allowing users to monitor and identify when Keeper rejects write requests because it has reached its soft memory limit. This helps in diagnosing memory pressure issues and improving system reliability.

How to use it

Users can track the new ProfileEvent for Keeper write rejections by monitoring the corresponding profile events in system metrics or logs to gain insights into memory-related write refusals.