New exercise for Asynchronous programming in C#

[mdrakiburrahman]

It would be great to have an exercise on Async programming as it is used in many real world dotnet applications.

The Golang track had one called "Prallel Letter Frequency"that introduce Goroutines, which I found quite useful.

[ErikSchierboom]

We have the same exercise (https://github.com/exercism/csharp/tree/main/exercises/practice/parallel-letter-frequency), but it looks like the implementation is actually wrong and uses synchronous code. Would you be interested in converting the exercise to allow for asynchronous (rather: parallel) programming?

[mdrakiburrahman]

@ErikSchierboom - sure! I've never contributed a scenario to Exercism - but if you can point me the necessary reqs (Unit testing etc) and assign the issue to me, I'm happy to contribute.

[ErikSchierboom]

@mdrakiburrahman You don't even have to create a new scenario, just to update the existing one to accommodate for people using parallel execution. So what I think needs to be done is to change the Calculate method to return a Task<Dictionary<char, int>> instead of Dictionary<char, int>. This means updating three files:

• The stub file: https://github.com/exercism/csharp/blob/main/exercises/practice/parallel-letter-frequency/ParallelLetterFrequency.cs#L6. This file should have its Calculate signature changed to the above.
• The tests file: https://github.com/exercism/csharp/blob/main/exercises/practice/parallel-letter-frequency/ParallelLetterFrequencyTests.cs. The tests should all be using async tests that work with the Task-based Calculate method.
• The example file: https://github.com/exercism/csharp/blob/main/exercises/practice/parallel-letter-frequency/.meta/Example.cs This file should also be updated to use the new signature and then be modified toprocess the results in parallel.

Finally, you should also add yourself to the exercise's contributors list in https://github.com/exercism/csharp/blob/main/exercises/practice/parallel-letter-frequency/.meta/config.json#L5