Insert Lock, Read Lock, Dead Lock Concatency Control

[omymy1]

Future Request- Please implement Insert Lock, Update Lock, Read Lock, Dead Lock etc Concatency Control.
because if two user want to update same key value then it makes problem. Please add this feature is already implemented then let me know.

[vweevers]

See prior discussions: Level/levelup#691, Level/community#47, Level/levelup#133, Level/levelup#381.

And prior art: https://github.com/Level/awesome#atomicity.