A request to perform an availability forecast, i.e., querying the predicted inventory to find the total amount of available (and booked) clicks, impressions, revenue, unique users, and custom events that exist at a given Priority level (weight). These are calculated by applying the supplied targeting rules or new ads after the delivery of all existing campaigns with priority weights equal to or above the supplied Priority. The priority can be specified in two manners. Either by the Priority or PriorityId fields (only one of them can be defined) or by the priorities that are defined in the Flights when the NewAds field is passed. When the NewAds field is specified, the Targeting, Priority, and PriorityId fields cannot be, since all the targeting, capping, and priority rules will be encoded in the Flight and Ads passed in NewAds. Additionally, if the NewAds provided contain a flight that shares the same ID with another one from the Ad Platform inventory, the simulated deliveries to that booked flight will be considered as potentially available for any of the provided Ads from flight. Note that the available revenue is only calculated when the NewAds field is provided.