code: func (l *logger) Copy() Logger {
  	l2 := &logger{
  		level:          l.level,
  		output:         l.output,
  		fields:         map[string]interface{}{},
  		disablePooling: l.disablePooling,
  	}
  	for k, v := range l.fields {
  		l2.fields[k] = v
  	}
  	return l2
  }
docs: // Copy returns a copy of the logger