swift dispatchGroup

Swift DispatchGroup is a class in the Swift programming language that allows you to synchronize the execution of multiple tasks running on different threads. It helps you to manage the timing of asynchronous operations and avoid race conditions.

A DispatchGroup is a lightweight mechanism for tracking a group of tasks. You can add tasks to a group, and the group will notify you when all of the tasks have completed. You can also specify a timeout for the group, after which the group will notify you if any of the tasks have not completed.

Here is an example of how to use a DispatchGroup:

let group = DispatchGroup()

group.enter()
// run task 1
group.leave()

group.enter()
// run task 2
group.leave()

group.notify(queue: .main) {
    // both tasks have completed
}

In this example, we create a DispatchGroup called `group`. We then use the `enter()` and `leave()` methods to add two tasks to the group. The `notify()` method is called when both tasks have completed, and we can then perform any necessary actions.

You can also use a DispatchGroup to wait for a group of tasks to complete before continuing execution. Here's an example:

let group = DispatchGroup()

group.enter()
// run task 1
group.leave()

group.enter()
// run task 2
group.leave()

group.wait()
// both tasks have completed

In this example, we use the `wait()` method to wait for both tasks to complete before continuing execution. This can be useful if you need to ensure that all tasks have completed before performing additional actions.