Enumerates SkAdNetwork attribution credits.

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

| Enums ||
|---|---|
| ## `CONTRIBUTED` | Google qualified for attribution, but didn't win. |
| ## `UNAVAILABLE` | The value was not present in the postback or we do not have this data for other reasons. |
| ## `UNKNOWN` | The value is unknown in this API version. The true enum value cannot be returned in this API version or is not supported yet. |
| ## `UNSPECIFIED` | Default value. This value is equivalent to null. |
| ## `WON` | Google was the ad network that won ad attribution. |