default.go
func Logf(level Level, format string, a ...interface{}) {
	getDefaultLogger().log(level, format, a...)
}
func Logf(level Level, format string, a ...interface{}) {
	getDefaultLogger().log(level, format, a...)
}
func Logf ( level Level , format string , a ... interface { } ) { getDefaultLogger ( ) . log ( level , format , a ... ) }
// Logf logs provided message with formatting with default logger.
Logf logs provided message with formatting with default logger .