Related discussion #7257Resolves#3413Resolves#5059Resolves#6258Resolves#7179
Adds a logging implementation that'll collect agent logs in memory until
slf4j is detected in the instrumented application; and when that happens
will dump all the logs into the application slf4j and log directly to
the application logger from that time on.
It's still in a POC state, unfortunately: while it works fine with an
app that uses & initializes slf4j directly, Spring Boot applications
actually reconfigure the logging implementation (e.g. logback) a while
after slf4j is loaded; which causes all the startup agent logs (debug
included) to be dumped with the default logback pattern.
Future work:
* ~~Make sure all logs produces by the agent are sent to loggers named
`io.opentelemetry...`
(https://github.com/open-telemetry/opentelemetry-java-instrumentation/pull/7446)~~
DONE
* Make this work on Spring Boot
* Documentation
* Smoke test?
Mateusz Rzeszutek