func (cursorCodec) ParseCursor(c string) (cursorData bson.D, err error) {
	var data []byte
	if data, err = base64.RawURLEncoding.DecodeString(c); err != nil {
		return
	}
	err = bson.Unmarshal(data, &cursorData)
	return
}
ParseCursor implements CursorCodec.ParseCursor().
package minquery
import (
	"encoding/base64"
	"github.com/globalsign/mgo/bson"
)
type CursorCodec interface {
	CreateCursor(cursorData bson.D) (string, error)
	ParseCursor(c string) (cursorData bson.D, err error)
}
type cursorCodec struct{}
func (cursorCodec) CreateCursor(cursorData bson.D) (string, error) {
	data, err := bson.Marshal(cursorData)
	return base64.RawURLEncoding.EncodeToString(data), err
}