code: func (do *Domain) GetSnapshotInfoSchema(snapshotTS uint64) (infoschema.InfoSchema, error) {
  	snapHandle := do.infoHandle.EmptyClone()
  	// For the snapHandle, it's an empty Handle, so its usedSchemaVersion is initialVersion.
  	_, _, _, err := do.loadInfoSchema(snapHandle, initialVersion, snapshotTS)
  	if err != nil {
  		return nil, err
  	}
  	return snapHandle.Get(), nil
  }
docs: // GetSnapshotInfoSchema gets a snapshot information schema.