code: func (d DataType) Zero() interface{} {
  	switch d {
  	case Float:
  		return zeroFloat64
  	case Integer:
  		return zeroInt64
  	case Unsigned:
  		return zeroUint64
  	case String, Tag:
  		return zeroString
  	case Boolean:
  		return zeroBoolean
  	case Time:
  		return zeroTime
  	case Duration:
  		return zeroDuration
  	}
  	return nil
  }
docs: // Zero returns the zero value for the DataType.
  // The return value of this method, when sent back to InspectDataType,
  // may not produce the same value.