rust-lang/rust — pull request #19946 by cgaebel (2014-12-17 03:33:35+00:00)
Title: [hashmap] Adds `drain`: a way to sneak out the elements while clearing a map.

It is useful to move all the elements out of a hashmap without deallocating
the underlying buffer. It came up in IRC, and this patch implements it as
`drain`.

r? @Gankro
cc: @frankmcsherry