Feture request: logger with different levels

[iSerganov]

As far as I can see from the README, for the moment there is only an option to provide a logger implementation that will log all internal messages of the library.

It would be very nice to have different levels of log messages, e.g.:

• Error
• Warn
• Info
• Debug

That will allow the caller code to choose the desirable amount of logged data depending on their need.

[isaacd9]

The Reader and Writer have both a Logger (for Info level logs) and an ErrorLogger for more serious errors: https://pkg.go.dev/github.com/segmentio/kafka-go#LoggerFunc

What messages do you think should be logged at Warn or Debug OOC?