log

type ErrorWithFields interface {
	error
	Fields() Fields
}

type Fields = map[string]interface{}

type Level uint8

type Logger interface {
	Level() Level

	WithField(key string, value interface{}) Logger
	WithFields(fields Fields) Logger
	WithError(err error) Logger

	Debugf(format string, args ...interface{})
	Infof(format string, args ...interface{})
	Warnf(format string, args ...interface{})
	Errorf(format string, args ...interface{})
	Panicf(format string, args ...interface{})

	Debug(args ...interface{})
	Info(args ...interface{})
	Warn(args ...interface{})
	Error(args ...interface{})
	Panic(args ...interface{})
}

type LoggerService interface {
	Logger
	Start(ctx context.Context) error
	Wait() <-chan error
}