There needs to be a way to shutdown logging and flush async appenders so when a process is closing, all log events are written before the process is closed.

Should ILoggerFactory have a shutdown or stop method? It could shutdown whatever logging back end I'm using?

For log4j it would call - org.apache.log4j.LogManager.getLoggerRepository().shutdown();
For logback it would call - loggerContext.stop()
Other back ends - ???

This is required to allow me to not reference logging back ends explicitly in my code to shutdown successfully without losing events.

Discussion about this is happening on the user list at -
http://www.qos.ch/pipermail/logback-user/2010-September/001816.html