isDisposing property
Whether the core is unwinding the cleanup stack.
The body is gone and the outcome is decided, but the job has not
finished: isFinished is still false.
A branch of JobContext.runAll answers true while it waits for the
group between the two passes of its unwinding, whether or not it has
a cleanup stack at all: what a branch may do while it is held must
not depend on that. Its outcome is not decided there — the group has
yet to say so.
Implementation
@protected
bool get isDisposing => _disposing;