mongodb/mongo-csharp-driver — comment on commit 4c1b6d2a80cf1b9b87157b9d758ebe63d864b9ef
File:  line 0
By rstam:

Two points:

1. if you get in and out of the lock fast enough then the chances of contention are very low and the simplest possible design may be good enough
2. once again, I don't think the non-generic versions of these methods are used (so it's moot, and certainly not worth optimizing further)