If task is cancelled all its dependents are cancelled, but not its children.

If cancelled task T is entering TERMINATE_WAIT state,
it renounces all its children and forwards parentage to transaction.
Once task T renounced its children it moves to TERMINATE state and
transaction undertakes T's children and their orchestration responsibility.
Transaction.abort() can be called only when transaction is in PREPARED state
Always properly rollback cancelled executing task.