Get Single Send Stats by ID

**This endpoint allows you to retrieve stats for an individual Single Send using a Single Send ID.** Multiple Single Send IDs can be retrieved using the "Get All Single Sends Stats" endpoint. Once you have an ID, this endpoint will return detailed stats for the Single Send specified. You may constrain the stats returned using the `start_date` and `end_date` query string parameters. You can also use the `group_by` and `aggregated_by` query string parameters to further refine the stats returned.