cameraDevice(_:shouldGetThumbnailOf:)
Tells the client when the camera is about to execute queued requests for the thumbnail of a specific item.
Declaration
optional func cameraDevice(_ cameraDevice: ICCameraDevice, shouldGetThumbnailOf item: ICCameraItem) -> BoolDiscussion
If the request is no longer needed—for example, if the item is no longer displayed on the screen—the client can cancel sending a request to the camera, speeding up the execution queue.