Defines a platform-neutral API for writing log messages. _Important! By default, no log writer function is registered, and so nothing is logged. Read on to learn how to properly configure logging for your application_ ## Adding logging to your module Log messages are written to a [[Logger]]. A canonical `Logger` instance for a package or module may be obtained by calling [[logger]]. Logger log = logger(`module hello`); The methods [[Logger.fatal]], [[Logger.error]], [[Logger.warn]], ...