add: duration_checked_sub RFC#1640

Merged

alexcrichton merged 3 commits intorust-lang:masterfrom

benaryorg:checked_sub

Aug 18, 2016

Commits on Jun 5, 2016

add: duration_checked_sub RFC
benaryorg
committed

Commits on Aug 11, 2016

add: list of methods to be implemented as of current state of discussion
benaryorg
committed

Commits on Aug 16, 2016

fix code for method
benaryorg
committed