log

type Logger interface {
	// Debug logs a debug level message.
	Debug(args ...interface{})

	// Debugf logs a debug level message with format.
	Debugf(format string, args ...interface{})

	// Debugln logs a debug level message. Spaces are always added between
	// operands.
	Debugln(args ...interface{})

	// Info logs an info level message.
	Info(args ...interface{})

	// Infof logs an info level message with format.
	Infof(format string, args ...interface{})

	// Infoln logs an info level message. Spaces are always added between
	// operands.
	Infoln(args ...interface{})

	// Warn logs a warn level message.
	Warn(args ...interface{})

	// Warnf logs a warn level message with format.
	Warnf(format string, args ...interface{})

	// Warnln logs a warn level message. Spaces are always added between
	// operands.
	Warnln(args ...interface{})

	// Error logs an error level message.
	Error(args ...interface{})

	// Errorf logs an error level message with format.
	Errorf(format string, args ...interface{})

	// Errorln logs an error level message. Spaces are always added between
	// operands.
	Errorln(args ...interface{})
}