Mutually exclusive states / consistent reporting

[dturn]

_succeeded?, _failed?, _timed_out? and (effectively) _ignored? should all be mutually exclusive, but there's nothing forcing them to be, and if they aren't in practice, what we'll show depends on what the caller decided to check first.

We should improve this situation since its likely to lead to reporting bugs / our reporting code is already getting complicated.

1 idea is to carefully define states and have the sync method move us through them..

cc: @KnVerey