switch_impl: adding a barrier_in handler
switch_impl: adding a barrier_in handler

--HG--
extra : transplant_source : %ECr/h%9ET%92%97%13_%0B%E3%E0%D7%3DX%AB%87%B5%84

MurphyMc/pox,denovogroup/pox,noxrepo/pox,waltznetworks/pox,chenyuntc/pox,waltznetworks/pox,MurphyMc/pox,xAKLx/pox,kpengboy/pox-exercise,adusia/pox,VamsikrishnaNallabothu/pox,jacobq/csci5221-viro-project,jacobq/csci5221-viro-project,denovogroup/pox,andiwundsam/_of_normalize,xAKLx/pox,pthien92/sdn,waltznetworks/pox,kavitshah8/SDNDeveloper,VamsikrishnaNallabothu/pox,kulawczukmarcin/mypox,carlye566/IoT-POX,MurphyMc/pox,VamsikrishnaNallabothu/pox,chenyuntc/pox,diogommartins/pox,andiwundsam/_of_normalize,pthien92/sdn,PrincetonUniversity/pox,PrincetonUniversity/pox,pthien92/sdn,diogommartins/pox,andiwundsam/_of_normalize,carlye566/IoT-POX,kulawczukmarcin/mypox,kulawczukmarcin/mypox,diogommartins/pox,PrincetonUniversity/pox,jacobq/csci5221-viro-project,pthien92/sdn,diogommartins/pox,PrincetonUniversity/pox,andiwundsam/_of_normalize,kulawczukmarcin/mypox,VamsikrishnaNallabothu/pox,noxrepo/pox,chenyuntc/pox,carlye566/IoT-POX,kulawczukmarcin/mypox,xAKLx/pox,VamsikrishnaNallabothu/pox,carlye566/IoT-POX,kavitshah8/SDNDeveloper,kpengboy/pox-exercise,diogommartins/pox,denovogroup/pox,kpengboy/pox-exercise,noxrepo/pox,adusia/pox,MurphyMc/pox,kavitshah8/SDNDeveloper,PrincetonUniversity/pox,chenyuntc/pox,xAKLx/pox,denovogroup/pox,kpengboy/pox-exercise,pthien92/sdn,carlye566/IoT-POX,xAKLx/pox,jacobq/csci5221-viro-project,adusia/pox,waltznetworks/pox,kavitshah8/SDNDeveloper,adusia/pox,denovogroup/pox,kpengboy/pox-exercise,chenyuntc/pox,waltznetworks/pox,adusia/pox,jacobq/csci5221-viro-project,noxrepo/pox,MurphyMc/pox