Product availability.

[Proto definition ![GitHub](https://developers.google.com/site-assets/logo-github.svg)](https://github.com/googleapis/googleapis/blob/master/google/ads/googleads/v25/enums/product_availability.proto)

| Enums ||
|---|---|
| ## `IN_STOCK` | The product is in stock. |
| ## `OUT_OF_STOCK` | The product is out of stock. |
| ## `PREORDER` | The product can be preordered. |
| ## `UNKNOWN` | Used for return value only. Represents values unknown in this version. |
| ## `UNSPECIFIED` | Enum unspecified. |