• Ensure the tests and linter pass
• Code coverage does not decrease (if any source code was changed)
• Appropriate docs were updated (if necessary)

#ToDo

• Add System test
• Add Samples for
  • Backup#restoreTo()
  • Instance#createTableFromBackup()

This PR proposes the following design

• Introduce an additional function Backup#restoreTo(config, callback?) which accepts a config parameter of the type

  export interface RestoreTableConfig {
    tableId: string;
    instance?: Instance | string;
    gaxOptions?: CallOptions;
  }

• Backup#restore() delegates to Backup#restoreTo() with this.cluster.instance value for config.instance.
• Instance#createTableFromBackup() now respects both
  • Backup object created on a different instance.
  • As well as a string of full backup name (path) that contains a different (form this.id) instanceId.

Other design options

!Breaking:

• Replace Backup#restore() with the proposed Backup#restoreTo() implementation
• Include the changes with current pending 4.0.0 release

Non Breaking:

• Add an optional instance parameter to Backup#restore()
  • This design might be a bit messier than desired

    restore(
      tableId: string,
      instanceOrGaxOptionsOrCallback?:
        | Instance
        | string
        | CallOptions
        | RestoreTableCallback,
      gaxOptionsOrCallback?: CallOptions | RestoreTableCallback,
      cb?: RestoreTableCallback
    ): void | Promise<RestoreTableResponse> {...}

  • This design will diverge from the established pattern

     function(OneRequiredParamIfAny, optionsOrCallback?, callback?) {...}