Enum describing possible serving statuses.

[Proto definition ![GitHub](https://developers.google.com/site-assets/logo-github.svg)](https://github.com/googleapis/googleapis/blob/master/google/ads/googleads/v26/enums/ad_serving_optimization_status.proto)

| Enums ||
|---|---|
| ## `CONVERSION_OPTIMIZE` | Ad serving is optimized based on clickthrough rate (CTR) \* Conversion for the campaign. If the campaign is not in the conversion optimizer bidding strategy, it will default to OPTIMIZED. |
| ## `OPTIMIZE` | Ad serving is optimized based on clickthrough rate (CTR) for the campaign. |
| ## `ROTATE` | Ads are rotated evenly for 90 days, then optimized for clicks. |
| ## `ROTATE_INDEFINITELY` | Show lower performing ads more evenly with higher performing ads, and do not optimize. |
| ## `UNAVAILABLE` | Ad serving optimization status is not available. |
| ## `UNKNOWN` | The received value is not known in this version. This is a response-only value. |
| ## `UNSPECIFIED` | No value has been specified. |