Before a request is issued, the internal __request property is None.
Previously, this meant that the arrived property would return False before
a request was issued, which is technically not an accurate response.
Additionally, the revive() command would throw an error since you can't set
the request to be None.

Here we make the default arrived value to be True, which is more accurate,
and revive() becomes a no-op if there is no request set.