adt: fast path Stab in empty interval tree
adt: fast path Stab in empty interval tree

mqliang/etcd,dannysauer/etcd,cockroachdb/etcd,cockroachdb/etcd,ravigadde/etcd,CrazyJvm/etcd,joshix/etcd,rnaveiras/etcd,yudai/etcd,tguangch/etcd,sinsharat/etcd,bdarnell/etcd,lumjjb/etcd,nekto0n/etcd,li-ang/etcd,visheshnp/etcd,nekto0n/etcd,coreos/etcd,glevand/coreos--etcd,plasticbox/etcd,etcd-io/etcd,luxas/etcd,bluebreezecf/etcd,akauppi/etcd,xiang90/etcd,YuleiXiao/etcd,ajityagaty/etcd,bdarnell/etcd,whuwxl/etcd,akauppi/etcd,lorneli/etcd,lorneli/etcd,heyitsanthony/etcd,bluebreezecf/etcd,vimalk78/etcd,gyuho/etcd,luxas/etcd,rnaveiras/etcd,ravigadde/etcd,jlamillan/etcd,hongchaodeng/etcd,YuleiXiao/etcd,glevand/coreos--etcd,a-robinson/etcd,sebrandon1/etcd,insequent/etcd,fanminshi/etcd,endocode/etcd,visheshnp/etcd,plasticbox/etcd,gyuho/etcd,armstrongli/etcd,sebrandon1/etcd,yudai/etcd,mkumatag/etcd,etcd-io/etcd,heyitsanthony/etcd,qqsun8819/etcd,etcd-io/etcd,CrazyJvm/etcd,handsomesun/etcd,mickep76/etcd,li-ang/etcd,mqliang/etcd,rchicoli/etcd,vimalk78/etcd,jlamillan/etcd,lumjjb/etcd,armstrongli/etcd,joshix/etcd,hongchaodeng/etcd,dannysauer/etcd,rchicoli/etcd,rnaveiras/etcd,qqsun8819/etcd,OyTao/etcd_learning,ajityagaty/etcd,zaphod-concur/etcd,OyTao/etcd_learning,sinsharat/etcd,zaphod-concur/etcd,ajityagaty/etcd,xiang90/etcd,mkumatag/etcd,mqliang/etcd,mkumatag/etcd,tguangch/etcd,a-robinson/etcd,whuwxl/etcd,fanminshi/etcd,coreos/etcd,handsomesun/etcd,mickep76/etcd,insequent/etcd,endocode/etcd