Manages long-running operations with an API service.

When an API method normally takes long time to complete, it can be designed to return `https://developers.google.com/merchant/api/reference/rpc/google.longrunning/Types/Operation` to the client, and the client can use this interface to receive the real response asynchronously by polling the operation resource, or pass the operation resource to another API (such as Pub/Sub API) to receive the response. Any API service that returns long-running operations should implement the `Operations` interface so developers can have a consistent client experience.

| [GetOperation](https://developers.google.com/merchant/api/reference/rpc/google.longrunning/Operations/GetOperation) |
|---|
| `` rpc GetOperation(`https://developers.google.com/merchant/api/reference/rpc/google.longrunning/Types/GetOperationRequest`) returns (`https://developers.google.com/merchant/api/reference/rpc/google.longrunning/Types/Operation`) `` Gets the latest state of a long-running operation. Clients can use this method to poll the operation result at intervals as recommended by the API service. Authorization scopes :   Requires the following OAuth scope: - `https://www.googleapis.com/auth/content` For more information, see the [OAuth 2.0 Overview](https://developers.google.com/identity/protocols/OAuth2). |