Explain the difference between DispatchQueue.main.async and DispatchQueue.main.sync ?

In Swift, DispatchQueue.main.async and DispatchQueue.main.sync are two methods used to manage the execution of code on the main thread, but they have significant differences in their behavior and use cases.

DispatchQueue.main.async

• Asynchronous Execution: When you use DispatchQueue.main.async, the code inside the closure is dispatched to the main queue and executed asynchronously. This means that the function returns immediately, and the code inside the closure is scheduled to run at some point in the future, without blocking the current thread.
• Non-blocking: Since the function returns immediately, it does not block the current thread. This is particularly useful for updating the UI or performing tasks that should not interrupt the flow of the current execution.
• Use Case: DispatchQueue.main.async is typically used for updating the user interface or performing tasks that need to be done on the main thread but should not block the current execution. For example:
  swift Copy

  DispatchQueue.main.async {
      self.imageView.image = image
      self.label.text = "Updated"
  }

DispatchQueue.main.sync

• Synchronous Execution: When you use DispatchQueue.main.sync, the code inside the closure is dispatched to the main queue and executed synchronously. This means that the function does not return until the code inside the closure has finished executing.
• Blocking: Since the function waits for the closure to complete, it blocks the current thread. If DispatchQueue.main.sync is called from the main thread, it will cause a deadlock because the main thread is waiting for itself to finish executing the closure, which it cannot do because it is blocked.
• Use Case: DispatchQueue.main.sync is rarely used directly on the main queue due to the risk of deadlock. It is more commonly used on background threads when you need to perform a task on the main thread and wait for it to complete before continuing. For example:
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  DispatchQueue.global().async {
      // Perform some background task
      DispatchQueue.main.sync {
          // Update the UI after the background task is comp...