func (d Data) Clone() Data {
	if d == nil {
		return nil
	}
	cpy := make(Data)
	for k, v := range d {
		cpy[k] = v
	}
	return cpy
}
Clone returns a copy of d.
package meta
import (
	"encoding/json"
	"fmt"
	"math"
)
type entryType int
const (
	_ entryType = iota
	metaStringType
	metaInt64Type
	metaUInt64Type
	metaFloat64Type
	metaBoolType
)
type Data map[string]Entry