tree be1d7c004220603165e60ce6d1f04cecb9ddfe8a
parent 1230a67e2eac5da6221e3ea428bbc7d98f4c021d
author Rain <rain1@fb.com> 1587672307 -0700
committer Anton Kochkov <xvilka@gmail.com> 1589353792 +0800

[visit] access original edge reference from a reversed edge

This can be useful when one is trying to write code that is always
interested in the original edge reference, whether the graph under
consideration is reversed or not.