Removing synchronization between unsubscribe and pollQueue.

Signed-off-by: David Marques <dpsmarques@gmail.com>
Properly handling upstream and downstream subscriptions.

If an unsubscribe call comes from the child, it will stop the
worker immediately, but upstream calls are scheduled allowing
downstream propagation.

Signed-off-by: David Marques <dpsmarques@gmail.com>