Bug fix: Distributed Function
Bug fix: Distributed Function

Add logic to prevent a distributed function holder to be cancelled/disposed multiple times.

YuxiaoHu/Prajna,BrunoBozza/Prajna,jinlmsft/Prajna,jinlmsft/Prajna,BrunoBozza/Prajna,MSRCCS/Prajna,BrunoBozza/Prajna,hongzhili/Prajna,BrunoBozza/Prajna,MSRCCS/Prajna,jinlmsft/Prajna,YuxiaoHu/Prajna,jinlmsft/Prajna,MSRCCS/Prajna,MSRCCS/Prajna,hongzhili/Prajna