Amoung other things, this makes unlocking a WORM backed file and then
re-adding it without making any changes not add a new object, as the
timestamp is preserved.
This drops the >>! and >>? with the nice low fixity. IfElse does have
undocumented >>=>>! and >>=>>? operators, but I deem that too fishy.
Anyway, using whenM and unlessM is easier; I sometimes mixed the operators
up.
