What types of queues exist and what are their features?

• Main Queue:
  • Type: Serial.
  • Feature: Executes tasks on the main thread of the user interface. All UI updates should occur here.
• Global Queues:
  • Type: Concurrent.
  • Features: Multiple queues with different priorities (High, Default, Low, Background). Tasks can run simultaneously, but their completion order is not guaranteed. Suitable for resource-intensive operations unrelated to UI.
• Custom Queues:
  • Type: Can be Serial or Concurrent.
  • Features: Created by the developer for specific purposes. Allow isolating tasks and managing their execution.

Queue Type	Typical Usage	UI Safety
Main	UI updates, handling UI events	Yes
Global	Background computations, network requests	No
Custom	Organizing specific background tasks, isolation	Depends on implementation

Example of creating a custom queue:

let customQueue = DispatchQueue(label: "com.example.myqueue", attributes: .concurrent)