Default returns a defulat logger.

DoLazyEval returns LazyEval.

NewLogger creates and returns new logger using a current setting.

PanicInvoker returns caller's location (file and line) that causes panic.

SkipCaller returns caller's location (file and line) to help debug.

Logger keeps configrations, and provides a funcs to print logs.

LazyEval can be used to evaluate an argument under a correct log level.