It's currently a test-only command and is broken in several subtle ways. We should just kill completely.
resync command has been removed
resync should reset drop-pending collection reaper state
Ensure concurrent resync works on secondaries
Reenable resync command for replica sets
Remove all code related to resync command
Fix replication and sharding tests to work with RTT
Allow dropDatabase (and dropCollection) to succeed when index build is in progress