flufl.lock sleeps random amount of time #2860
Description
https://gitlab.com/warsaw/flufl.lock/blob/master/flufl/lock/_lockfile.py#L274 Happens whenever lock is taken. So this results in dvc freezeing at the begging of any operation, when it checks the updater lock. Related to #2831 . Need to consider bringing back zc.lockfile as described there and only falling back to flufl when flock() is not working.