AsyncEnumerator 1.4.2

Introduces IAsyncEnumerable, IAsyncEnumerator, ForEachAsync(), and ParallelForEachAsync()
GitHub: https://github.com/tyrotoxin/AsyncEnumerable

PROBLEM SPACE

Helps to (a) create an element provider, where producing an element can take a lot of time
due to dependency on other asynchronous events (e.g. wait handles, network streams), and
(b) a consumer that processes those element as soon as they are ready without blocking
the thread (the processing is scheduled on a worker thread instead).


EXAMPLE

using System.Collections.Async;

static IAsyncEnumerable<int> ProduceAsyncNumbers(int start, int end)
{
 return new AsyncEnumerable<int>(async yield => {

   // Just to show that ReturnAsync can be used multiple times
   await yield.ReturnAsync(start);

   for (int number = start + 1; number <= end; number++)
     await yield.ReturnAsync(number);

   // You can break the enumeration loop with the following call:
   yield.Break();

   // This won't be executed due to the loop break above
   await yield.ReturnAsync(12345);
 });
}

// Just to compare with synchronous version of enumerator
static IEnumerable<int> ProduceNumbers(int start, int end)
{
 yield return start;

 for (int number = start + 1; number <= end; number++)
   yield return number;

 yield break;

 yield return 12345;
}

static async Task ConsumeNumbersAsync()
{
 var asyncEnumerableCollection = ProduceAsyncNumbers(start: 1, end: 10);
 await asyncEnumerableCollection.ForEachAsync(async number => {
   await Console.Out.WriteLineAsync($"{number}");
 });
}

// Just to compare with synchronous version of enumeration
static void ConsumeNumbers()
{
 // NOTE: IAsyncEnumerable is derived from IEnumerable, so you can use either
 var enumerableCollection = ProduceAsyncNumbers(start: 1, end: 10);
 //var enumerableCollection = ProduceNumbers(start: 1, end: 10);

 foreach (var number in enumerableCollection) {
   Console.Out.WriteLine($"{number}");
 }
}

There is a newer version of this package available.
See the version list below for details.
Install-Package AsyncEnumerator -Version 1.4.2
dotnet add package AsyncEnumerator --version 1.4.2
paket add AsyncEnumerator --version 1.4.2
The NuGet Team does not provide support for this client. Please contact its maintainers for support.

Release Notes

1.4.2: Add finalizer to AsyncEnumerator and call Dispose in ForEachAsync and ParallelForEachAsync extension methods.
1.4.0: Add new generic type AsyncEnumeratorWithState for performance optimization.
      Now IAsyncEnumerator<T> is covariant.
      Add ForEachAsync, ParallelForeachAsync, and LINQ-style extension methods for IAsyncEnumerator.
1.3.0: Significantly improve performance of AsyncEnumerator by reducing thread switching and re-using instances of TaskCompletionSource.
      Add support for a state object that can be passed into AsyncEnumerable and AsyncEnumerator for performance optimization.
      Remove CancellationToken from Select/Take/Skip/Where extension methods - fix improper implementation.
      Move AsyncEnumerationCanceledException out of the generic AsyncEnumerator type.
      Change default behavior of the ToAsyncEnumerable extension method - now MoveNextAsync will run synchronously by default.
1.2.3: AsyncEnumerationCanceledException is thrown to the async enumeration function when the AsyncEnumerator is disposed before reaching the end of enumeration, what allows to do the clean-up.
      Fixed MoveNextAsync() that threw an exception sometimes only when you passed the end of enumeration.
1.2.2: Fix exception propagation in AsyncEnumerator.
1.2.1: New Linq-style extension methods in System.Collections.Async namespace.
1.2.0: Contract breaking changes in ParallelForEachAsync: introduce ParallelForEachException to unify error outcome of the loop.
1.1.0: Add ParallelForEachAsync extension methods for IEnumerable<T> and IAsyncEnumerable<T> in System.Collections.Async namespace.

Dependencies

This package has no dependencies.

Version History

Version Downloads Last updated
3.0.2-beta 106 4/9/2019
3.0.0-beta1 1,704 2/23/2019
2.2.2 29,074 1/27/2019
2.2.1 248,332 5/29/2018
2.2.0 8,742 5/18/2018
2.1.1 63,086 1/20/2018
2.1.0 128,731 5/22/2017
2.0.1 39,747 2/13/2017
1.5.0 2,665 2/12/2017
1.4.2 941 2/6/2017
1.3.0 1,219 1/20/2017
1.2.3 6,240 1/6/2017
1.2.2 1,052 12/11/2016
1.2.1 294 12/10/2016
1.2.0 8,337 11/29/2016
1.1.3 306 11/28/2016
1.1.2 13,081 8/29/2016
1.0.3 1,539 4/28/2016
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