allow plugins to signal esworker to drop a message
allow plugins to signal esworker to drop a message

526avijitgupta/MozDef,jvehent/MozDef,triplekill/MozDef,DarkPrince304/MozDef,triplekill/MozDef,mozilla/MozDef,abhijithch/MozDef,jeffbryner/MozDef,gdestuynder/MozDef,serbyy/MozDef,gsssrao/MozDef,mpurzynski/MozDef,526avijitgupta/MozDef,eXcomm/MozDef,mpurzynski/MozDef,Phrozyn/MozDef,triplekill/MozDef,jeffbryner/MozDef,ameihm0912/MozDef,jvehent/MozDef,netantho/MozDef,jvehent/MozDef,DarkPrince304/MozDef,DarkPrince304/MozDef,526avijitgupta/MozDef,mozilla/MozDef,gdestuynder/MozDef,eXcomm/MozDef,ameihm0912/MozDef,mpurzynski/MozDef,gdestuynder/MozDef,abhijithch/MozDef,eXcomm/MozDef,ameihm0912/MozDef,DarkPrince304/MozDef,gdestuynder/MozDef,serbyy/MozDef,Phrozyn/MozDef,eXcomm/MozDef,Phrozyn/MozDef,abhijithch/MozDef,526avijitgupta/MozDef,netantho/MozDef,abhijithch/MozDef,mozilla/MozDef,jeffbryner/MozDef,netantho/MozDef,gsssrao/MozDef,serbyy/MozDef,gsssrao/MozDef,triplekill/MozDef,jeffbryner/MozDef,mozilla/MozDef,mpurzynski/MozDef,gsssrao/MozDef,Phrozyn/MozDef,jvehent/MozDef,serbyy/MozDef,netantho/MozDef,ameihm0912/MozDef