Flush messages on close

[richardnagle]

This PR will ensure that on appender shutdown all queued messages are sent to loggly.

[mostlyjason]

Thanks @richardnagle! We'll review this when our engineer gets a chance.

[abedra]

@mostlyjason when do you expect to merge this?

[YouGitMoreWithLes]

I would really like to see this get merged and released. I have a few console applications using this dependency and I must add a wait loop until the timer fires to flush the logs.

[Katulus]

The current implementation still does not guarantee that all logs are sent. Because messages are taken out of queue before they are sent over the wire the Flush call can return before logs are really sent over the wire. If you then terminate application you lose logs.

We plan to do some refactoring of this so we'll try to include proper flush on shutdown.

[Katulus]

New version (beta) has been just released. You can get it on https://github.com/loggly/log4net-loggly/releases/tag/v9.0.0-beta1 or via Nuget. It's almost complete rewrite and flush-on-shutdown is now included.