Split out a map from a fold
Split out a map from a fold

Summary: This is simpler and it makes some of my upcoming changes easier

Reviewed By: panagosg7

Differential Revision: D10115687

fbshipit-source-id: 63dc1de6055e5365e3d72a8169a140c9bc4e9f91

AgentME/flow,facebook/flow,AgentME/flow,gabelevi/flow,facebook/flow,facebook/flow,facebook/flow,gabelevi/flow,gabelevi/flow,jamesgpearce/flow,gabelevi/flow,jamesgpearce/flow,popham/flow,mroch/flow,gabelevi/flow,AgentME/flow,samwgoldman/flow,jamesgpearce/flow,mroch/flow,samwgoldman/flow,AgentME/flow,mroch/flow,mroch/flow,popham/flow,facebook/flow,mroch/flow,samwgoldman/flow,samwgoldman/flow,popham/flow,mroch/flow,jamesgpearce/flow,jamesgpearce/flow,gabelevi/flow,popham/flow,AgentME/flow,jamesgpearce/flow,mroch/flow,jamesgpearce/flow,gabelevi/flow,samwgoldman/flow,samwgoldman/flow,samwgoldman/flow,facebook/flow,facebook/flow,popham/flow,popham/flow,popham/flow