add keepalive logic
add keepalive logic

vmware/rbvmomi,10xEngineer/rbvmomi,rlane/rbvmomi,rapid7/rbvmomi,logankimmel/rbvmomi,frapposelli/vagrant-rbvmomi,synthead/rbvmomi,frapposelli/vagrant-rbvmomi,10xEngineer/rbvmomi,omar-infinio/rbvmomi,jusko/rbvmomi,rcorrieri/rbvmomi,synthead/rbvmomi,rlane/rbvmomi,jusko/rbvmomi,rapid7/rbvmomi