Adding ConfigureAwait.

Ix.NET/Source/System.Linq.Async/System/Threading/Tasks/AsyncEnumerableExtensions.cs

@@ -0,0 +1,58 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the Apache 2.0 License.
+// See the LICENSE file in the project root for more information. 
+
+using System.Collections.Generic;
+using System.Runtime.CompilerServices;
+
+namespace System.Threading.Tasks
+{
+    namespace System.Threading.Tasks
+    {
+        public static class AsyncEnumerableExtensions
+        {
+            public static ConfiguredAsyncEnumerable<T> ConfigureAwait<T>(this IAsyncEnumerable<T> enumerable, bool continueOnCapturedContext)
+            {
+                if (enumerable == null)
+                    throw new ArgumentNullException(nameof(enumerable));
+
+                return new ConfiguredAsyncEnumerable<T>(enumerable, continueOnCapturedContext);
+            }
+
+            public struct ConfiguredAsyncEnumerable<T>
+            {
+                private readonly IAsyncEnumerable<T> _enumerable;
+                private readonly bool _continueOnCapturedContext;
+
+                internal ConfiguredAsyncEnumerable(IAsyncEnumerable<T> enumerable, bool continueOnCapturedContext)
+                {
+                    _enumerable = enumerable;
+                    _continueOnCapturedContext = continueOnCapturedContext;
+                }
+
+                public ConfiguredAsyncEnumerator GetAsyncEnumerator() =>
+                    new ConfiguredAsyncEnumerator(_enumerable.GetAsyncEnumerator(), _continueOnCapturedContext);
+
+                public struct ConfiguredAsyncEnumerator
+                {
+                    private readonly IAsyncEnumerator<T> _enumerator;
+                    private readonly bool _continueOnCapturedContext;
+
+                    internal ConfiguredAsyncEnumerator(IAsyncEnumerator<T> enumerator, bool continueOnCapturedContext)
+                    {
+                        _enumerator = enumerator;
+                        _continueOnCapturedContext = continueOnCapturedContext;
+                    }
+
+                    public ConfiguredTaskAwaitable<bool> MoveNextAsync() =>
+                        _enumerator.MoveNextAsync().ConfigureAwait(_continueOnCapturedContext);
+
+                    public T Current => _enumerator.Current;
+
+                    public ConfiguredTaskAwaitable DisposeAsync() =>
+                        _enumerator.DisposeAsync().ConfigureAwait(_continueOnCapturedContext);
+                }
+            }
+        }
+    }
+}