More often than not, users wish to customize not only the output destination but also the output format. This is accomplished by associating a Layout with a LogTarget. The Layout is responsible for formatting the LogEvent to the user's wishes, whereas a log target takes care of sending the formatted output to its destination.
Every layout should extend this class which currently provides haxe.PosInfos formatting.
Differentiates between ExpressionMessage and every other message where for expressions it doesn't print any additional information except the expression itself. Particularly useful in macro context.