Pass Status reference in status callbacks

[teddyrendahl]

Status objects callbacks are called with no arguments. This means to even have some simple logic based on the completion of the status you need to use partials. I think passing the status back to the user would be a nice usability improvement. We can always inspect signatures to keep back-compat.

[tacaswell]

This seems like a good idea to me.

It should be coordinated with a change to bluesky to use this mechanism rather than closures to inject the status object into the callback.