contrib/raftexample: Restrict channel types
contrib/raftexample: Restrict channel types

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