Creates a new dispatch queue to which you can submit blocks.
convenience init(
label: String,
qos: DispatchQoS = .unspecified,
attributes: DispatchQueue.Attributes = [],
autoreleaseFrequency: DispatchQueue.AutoreleaseFrequency = .inherit,
target: DispatchQueue? = nil
)
label
A string label to attach to the queue to uniquely identify it in debugging tools such as Instruments, sample, stackshots, and crash reports. Because applications, libraries, and frameworks can all create their own dispatch queues, a reverse-DNS naming style (com.example.myqueue) is recommended. This parameter is optional and can be NULL.**qos**The quality-of-service level to associate with the queue. This value determines the priority at which the system schedules tasks for execution. For a list of possible values, see DispatchQoS.QoSClass.
attributes
The attributes to associate with the queue. Include the concurrent attribute to create a dispatch queue that executes tasks concurrently. If you omit that attribute, the dispatch queue executes tasks serially.
autoreleaseFrequency
The frequency with which to autorelease objects created by the blocks that the queue schedules. For a list of possible values, see DispatchQueue.AutoreleaseFrequency.
**target**The target queue on which to execute blocks. Specify DISPATCH_TARGET_QUEUE_DEFAULT if you want the system to provide a queue that is appropriate for the current object
Creating a Dispatch Queue