filter log messages based on module, when using the json logger format.

[madelaney]

I was looking at json_logger.rs, but it was unclear how I can filter the messages based on the module. For example, if I just want the module that is setting up log4rs to actually log messages.

[madelaney]

I found out I can do something like .logger(Logger::builder().build("other_module", LevelFilter::Off)), but I'm still curious if I can turn off everything except the root module without having to list the other modules.