[split] Var.collect: Fix deadlock caused by oversynchronizing
[split] Var.collect: Fix deadlock caused by oversynchronizing

RB_ID=304539

travisbrown/util,tdyas/util,hydro2k/util,tdyas/util,BuoyantIO/twitter-util,twitter/util,nkhuyu/util,tenghuihua/util,twitter/util,hydro2k/util,hydro2k/util,slackhappy/util,luciferous/util,RUNDSP/util,LitmusHealth/twitter-utils,Jiri-Kremser/util,edombowsky/util,BuoyantIO/twitter-util,travisbrown/util,wuqiangxjtu/util,stremlenye/util,tenghuihua/util,edombowsky/util,stremlenye/util,tenghuihua/util,slackhappy/util,travisbrown/util,Jiri-Kremser/util,stremlenye/util,slackhappy/util,nkhuyu/util,hydro2k/util,folone/util,LitmusHealth/twitter-utils,wuqiangxjtu/util,Jiri-Kremser/util,stremlenye/util,cogitate/twitter-util-uuid,LitmusHealth/twitter-utils,luciferous/util,cogitate/twitter-util-uuid,folone/util,edombowsky/util,folone/util,travisbrown/util,tenghuihua/util,nkhuyu/util,mosesn/util,LitmusHealth/twitter-utils,folone/util,luciferous/util,cogitate/twitter-util-uuid,wuqiangxjtu/util,tdyas/util,RUNDSP/util,slackhappy/util,mosesn/util,cogitate/twitter-util-uuid,mosesn/util,Jiri-Kremser/util,twitter/util,RUNDSP/util,BuoyantIO/twitter-util,edombowsky/util,RUNDSP/util,nkhuyu/util,BuoyantIO/twitter-util,tdyas/util,luciferous/util,wuqiangxjtu/util