MainActor in Swift replaces DispatchQueue.main and ensures tasks are performing on the main thread in a performant manner.

MainActor is a new attribute introduced in Swift 5.5 as a global actor providing an executor which performs its tasks on the main thread. When building apps, it’s essential to perform UI updating tasks on the main thread, which can sometimes be challenging when using several background threads. Using the @MainActor attribute will help ensure your UI is always updated on the main thread.