Upload binary files diffs in parallel
Upload binary files diffs in parallel

Summary: Makes sense after D2471.

Test Plan:
Swapped two binary files, ran `arc diff --only`.
Saw time 3.797 s instead of 4.361 s.

Changed `file.upload` to `file.uploa`, saw proper error.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4847

haskell-infra/arcanist,codelabs-ch/arcanist,calblueprint/arcanist,zhihu/arcanist,alexmv/arcanist,Symplicity/arcanist,Symplicity/arcanist,fivestars/arcanist,PageUpPeopleOrg/arcanist-patches,wikimedia/phabricator-arcanist,Symplicity/arcanist,hach-que/arcanist,r4nt/arcanist,codelabs-ch/arcanist,haskell-infra/arcanist,wharris/arcanist,sneakpeeq/arcanist,coursera/arcanist,chundongwang/arcanist,calblueprint/arcanist,sneakpeeq/arcanist,coursera/arcanist,memsql/arcanist,jra3/arcanist,haskell-infra/arcanist,hach-que/arcanist,coursera/arcanist,folsom-labs/arcanist,julkiewicz/arcanist,uber/arcanist,r4nt/arcanist,PageUpPeopleOrg/arcanist-patches,julkiewicz/arcanist,phacility/arcanist,eSpark/arcanist,aik099/arcanist,KieranHayes/arcanist,hach-que/arcanist,KieranHayes/arcanist,codelabs-ch/arcanist,julkiewicz/arcanist,Symplicity/arcanist,uber/arcanist,wikimedia/phabricator-arcanist,uber/arcanist,zhihu/arcanist,folsom-labs/arcanist,codelabs-ch/arcanist,phacility/arcanist,zhihu/arcanist,phacility/arcanist,r4nt/arcanist,calblueprint/arcanist,aik099/arcanist,folsom-labs/arcanist,haskell-infra/arcanist,sneakpeeq/arcanist,dguo-coursera/arcanist,eSpark/arcanist,jra3/arcanist,codelabs-ch/arcanist,zhihu/arcanist,wxstars/arcanist,dguo-coursera/arcanist,wharris/arcanist,wikimedia/phabricator-arcanist,julkiewicz/arcanist,sneakpeeq/arcanist,kevinseelbach/arcanist,folsom-labs/arcanist,kevinseelbach/arcanist,alexmv/arcanist,Khan/arcanist,wxstars/arcanist,wxstars/arcanist,chundongwang/arcanist,PageUpPeopleOrg/arcanist-patches,dguo-coursera/arcanist,coursera/arcanist,chundongwang/arcanist,dguo-coursera/arcanist,wharris/arcanist,fivestars/arcanist,alexmv/arcanist,jra3/arcanist,wxstars/arcanist,wharris/arcanist,phacility/arcanist,r4nt/arcanist,chundongwang/arcanist,Khan/arcanist,fivestars/arcanist,eSpark/arcanist,fivestars/arcanist,phacility/arcanist,kevinseelbach/arcanist,KieranHayes/arcanist,wikimedia/phabricator-arcanist,uber/arcanist,hach-que/arcanist,calblueprint/arcanist,aik099/arcanist,aik099/arcanist,alexmv/arcanist,memsql/arcanist,jra3/arcanist,memsql/arcanist,Khan/arcanist,eSpark/arcanist,KieranHayes/arcanist,Khan/arcanist,kevinseelbach/arcanist,memsql/arcanist,PageUpPeopleOrg/arcanist-patches