User-accessible logs

We often need to request logs from users. Sometimes it is a real PITA.

We need a way to easily gather and copy logs from within the app.

Standard `android.util.Log` doesn't provide any way to redirect or collect logs. It is possible to call `logcat` and gather the results, but it is ugly and has some limitations.

I was thinking about moving to [SLF4J](https://www.slf4j.org/) + [logback-android](https://tony19.github.io/logback-android/). It should allow to log to various outputs (standard Android logcat, file, etc.). Also, SLF4J's API is better (no need for explicit `String.format()` in logging). Though, it would require to replace all the `android.util.Log` usages.
I don't see any downsides of it.

Any other ideas?