Shuts down the log4net system.
Calling this method will safely close and remove all appenders in all the loggers including root contained in all the default repositories.
Some appenders need to be closed before the application exists. Otherwise, pending logging events might be lost.
The shutdown method is careful to close nested appenders before closing regular appenders. This is allows configurations where a regular appender is attached to a logger and again to a nested appender.
LoggerManager Class | log4net.Core Namespace