Set log level from command line

Is it possible to add documentation on how to set the log level of the Consumer? We'd like to log `WARN` and higher, we find that `INFO` is too verbose for us.

No documentation file, test, or entry point is named. Start by locating the Consumer logging configuration and existing command-line documentation, then document how to set the log level to WARN or higher; done when users can follow the documentation to avoid INFO-level output.

Written by the indexing model from the issue text.