Task Combinators and Cancellation

In previous lessons, we used await to wait for a single task. However, real-world applications often launch multiple operations simultaneously, such as downloading ten images, querying three different databases, or waiting for user input with a timeout.

Waiting for these tasks one by one defeats the purpose of concurrency. To handle this efficiently, C# provides task combinators: methods that combine multiple tasks into a single awaitable unit. Additionally, we need a safe way to stop these tasks if they take too long or if the user cancels the operation.

Waiting for all tasks (WhenAll)

The Task.WhenAll method accepts a collection of tasks and returns a single new task that completes only when all the provided tasks have finished. This is essential for running independent operations in parallel and waiting for the final result.