The details of the asset to add.
| Fields | |
|---|---|
| 
 | Output only. The asset field type of the asset(s) to add. | 
| 
 | 
 Output only. The number of assets to add. | 
| 
 | 
 Output only. For video field types, the required aspect ratio of the video. When unset and asset_field_type is YOUTUBE_VIDEO, the system recommends the advertiser upload any YouTube video, regardless of aspect ratio. |