Notifications on connection state changes and reconnection handling

[flxo]

Hi,

I scratched the notifications of the connection state. Instead of a plain crossbeam_channel::Receiver the notifications thing returned is struct that wraps this and a oneshot channel for the sender to detect if the receiving side is dropped.

Next I refactored the reconnection handling (think the AfterFirstSuccess was broken anyway ;-)) for pushing Errors along with Notification::Disconnected.

This PR tries to fix #139 and #82.

During implementing this patch I touhght the one or other time that merging ConnectError and ClientError is worth to consider. For the user a single Error type might also be more convenient.

I'm open for a discussion on the detail and expect comments!

Thanks,

@flxo

[tekjar]

Hi. Sorry for the late response. Kinda sick. I'll be able to check this on Thursday. I've started some clean up as well in connection_refactor branch along with test cases.

Is it possible to make this pull request only about notifications? I've made some changes to reconnection handling as well. Also it'll make my life easier reviewing and visiting back the feature in future

[flxo]

Hi, hope you're doing better!

The reason for the refactoring is that I'd love to include the Error in the Disconnect notification. Currently the error handling is interrupted at some points e.g. this Result<_, bool> thing and in order to get the Error where I needed it I had to shuffle things around.

Anyway. I started to rebase this patch on top of your connect_refactor brach. Its WIP here.

Hope I can finish that one till end of the week and will leave you a note here - or if everything is fine I'll do a PR against connection_refactor. Will try to not touch the reconnections behaviour :-)

cheers,

@flxo

[tekjar]

Will try to not touch the reconnections behaviour :-)

Thank you :)

[flxo]

Closing this in favour of #143.