Imported Upstream version 3.6.0

Former-commit-id: da6be194a6b1221998fc28233f2503bd61dd9d14

external/entityframework/src/EntityFramework/Infrastructure/IDbAsyncEnumerator.cs

@@ -0,0 +1,32 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
+
+
+#if !NET40
+
+namespace System.Data.Entity.Infrastructure
+{
+    using System.Collections;
+    using System.Threading;
+    using System.Threading.Tasks;
+
+    /// <summary>
+    ///     Asynchronous version of the <see cref="IEnumerator" /> interface that allows elements to be retrieved asynchronously.
+    ///     It is used to interact with Entity Framework queries and shouldn't be implemented by custom classes.
+    /// </summary>
+    public interface IDbAsyncEnumerator : IDisposable
+    {
+        /// <summary>
+        ///     Advances the enumerator to the next element in the sequence, returning the result asynchronously.
+        /// </summary>
+        /// <param name="cancellationToken"> The token to monitor for cancellation requests. </param>
+        /// <returns> A Task containing the result of the operation: true if the enumerator was successfully advanced to the next element; false if the enumerator has passed the end of the sequence. </returns>
+        Task<bool> MoveNextAsync(CancellationToken cancellationToken);
+
+        /// <summary>
+        ///     Gets the current element in the iteration.
+        /// </summary>
+        object Current { get; }
+    }
+}
+
+#endif