When certain operations take a very long amount of time waiting for locks, it's difficult to determine what they were waiting on unless it was a client operation and reported as slow. Non-client operations have no visibility.

Proposal: potentially in debug mode only, for now, report warnings in the log for operations that A) hold locks for long amounts of time (multiple seconds) and B) wait a long amount of time for locks. Traces would also be great, but maybe too noisy.

As an example, in testing we intermittently see activity stop and killCursors take > 30s to complete (waiting for locks), but no other client operations take nearly this amount of time.