Callable can take one of the following forms, where the second form is used when an asynchronous call can set the promise with a value that is only valid for the duration of the Callable call. This can be used when the previous continuation returned aTArray. The Callable will be called once per element in the previous result. The results will be combined into aTArrayResultType(AsyncOp, LastResultElement) AsyncOp is aFOnlineAsyncOp& or TOnlineAsyncOp& LastResultElement is a LastResultElementType or const LastResultElementType& ResultType is any type, or aTFutureto allow for an asynchronous result void(AsyncOp, LastResultElement, TPromise&&) AsyncOp is aFOnlineAsyncOp& or TOnlineAsyncOp& LastResultElement is a LastResultType or const LastResultType& ResultType is any non-void type