How to implement multi-threaded task processing in Swift using modern async/await asynchronous functions?

The modern approach to asynchronous programming in Swift replaces traditional closures and delegates with a more readable and linear syntax. Using the async and await keywords allows writing asynchronous code just as simply as synchronous code.

A function that performs heavy or network operations is marked with the async modifier. This indicates to the compiler that the execution of this function can be suspended at certain points in time without blocking the main UI thread.

When calling such a function in code, the await operator is used. At this point, the execution of the current method is suspended until the called method returns a result, while the thread can handle other interface tasks in the meantime.

For parallel execution of multiple independent tasks, the async let construct or TaskGroup is used. This allows launching several requests simultaneously and awaiting their completion, significantly reducing the total waiting time for the user.

For safe return from an asynchronous context to the main thread responsible for rendering graphics, actor isolation is used, such as MainActor. Marking a method with this attribute guarantees that the interface update will happen precisely on the main thread of the application.