Uniqueness validation should be removed.

[qubyte]

This defect was first logged here, but since it is now specific to the validations module I'll echo it here.

tl;dr - Uniqueness cannot be asserted the way it is here, since it is prone (and this happens often in the wild so it's not just theoretical) to race conditions. The function is not reliable, and therefore worse than useless and should be removed. Uniqueness should be provided by each adaptor, probably delegating to the database. e.g. in the case of redis-hq this would be implemented as a lua stored procedure.