Now if Add is to be called it will be called before Wait, this is achieved
by doing following:
- if cancel() gets lock first and closes channelCh before spawnSync is called
we will exit right away
- if not than we will ensure that we hold a lock until syncers are spawned
so that cancel() will be blocked for this time and it will prevent whole Terminate() from
progressing
Dmitry Shulyak
Pedro Pombeiro
Igor Mandrigin