Asynchronous operations

Some actions result in asynchronous operations. In such cases, the API will return a 202 status code with operation ID in relationships object.
The operation status can be checked by sending a GET request to /api/tag/v1/{app_id}/operations/{operation_id} URL.
An operation can be in one of the following states:
- created - The operation has been created but not yet started.
- started - The operation is in progress.
- completed - The operation finished successfully, and the result is available.
- failed - The operation encountered an error and did not complete successfully.
Operations can be identified by the operation_type attribute.
There can only be 1 operation of a given type (in state started or created) for a given resource (app) at a time.