Discussion You can use this method from within a running operation object to get a reference to the operation queue that started it.
Thus, it is still possible for low-priority operations to execute before high-priority operations in a different queue. static func ..< (Operation Queue.Scheduler Time Type, Operation Queue.Scheduler Time Type) -> Range Returns a half-open range that contains its lower bound but not its upper bound. Once added, the specified operation remains in the queue until it finishes executing.

An operation object can be in at most one operation queue at a time and this method throws an NSInvalid Argument Exception exception if the operation is already in another queue. For more information about using operation queues, see Concurrency Programming Guide. Important. Important. Operation queues retain operations until they're finished, and queues themselves are retained until all operations are finished. The operation queue that started the operation or nil if the queue could not be determined. This improves the performance of your app. An operation object can be in at most one operation queue at a time and this method throws an invalid Argument Exception exception if the operation is already in another queue. Once added, the specified operation remains in the queue until it finishes executing. Suspending an operation queue with operations that aren't finished can result in a memory leak. Suspending an operation queue with operations that aren't finished can result in a memory leak. If your application has multiple operation queues, each prioritizes its own operations independently of any other queues. Operation queues retain operations until they're finished, and queues themselves are retained until all operations are finished. This class contains two dictionaries to keep track of active and pending download and filter operations for each row in the table, and an operation queues for each type of operation. All of the values are created lazily — they aren’t initialized until they’re first accessed.