proposal: allow lock-free updates?

[gaissmai]

Dear users,

I have implemented an InsertPersist method in the persist branch, and before I go to the trouble of writing the same for DeletePersist and ~~UpdatePersist~~ ModifyPersist, I'm asking for a thumbs up or down on whether this would be used.

Please consider that the lock-free persist methods are in the microsecond range as opposed to nanoseconds for normal insert/delete.