To avoid an expensive call to archive.ChangesDirs() which walks two directory
trees and compares every entry, archive.ApplyLayer() has been extended to
also return the size of the layer changes.
Docker-DCO-1.1-Signed-off-by: Josh Hawn <josh.hawn@docker.com> (github: jlhawn)
This makes sure that we don't buffer in memory and that we also flush
stdin from diff as well as untar.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
