Move WithCancellation/ConfigureAwait extension methods

src/System.Threading.Tasks/ref/System.Threading.Tasks.cs

@@ -144,13 +144,16 @@ public void SetResult(TResult result) { }
         public bool TrySetException(System.Exception exception) { throw null; }
         public bool TrySetResult(TResult result) { throw null; }
     }
-    public static partial class TaskExtensions
+    public static partial class TaskAsyncEnumerableExtensions
     {
         public static System.Runtime.CompilerServices.ConfiguredAsyncDisposable ConfigureAwait(this System.IAsyncDisposable source, bool continueOnCapturedContext) { throw null; }
         public static System.Runtime.CompilerServices.ConfiguredCancelableAsyncEnumerable<T> ConfigureAwait<T>(this System.Collections.Generic.IAsyncEnumerable<T> source, bool continueOnCapturedContext) { throw null; }
+        public static System.Runtime.CompilerServices.ConfiguredCancelableAsyncEnumerable<T> WithCancellation<T>(this System.Collections.Generic.IAsyncEnumerable<T> source, System.Threading.CancellationToken cancellationToken) { throw null; }
+    }
+    public static partial class TaskExtensions
+    {
         public static System.Threading.Tasks.Task Unwrap(this System.Threading.Tasks.Task<System.Threading.Tasks.Task> task) { throw null; }
         public static System.Threading.Tasks.Task<TResult> Unwrap<TResult>(this System.Threading.Tasks.Task<System.Threading.Tasks.Task<TResult>> task) { throw null; }
-        public static System.Runtime.CompilerServices.ConfiguredCancelableAsyncEnumerable<T> WithCancellation<T>(this System.Collections.Generic.IAsyncEnumerable<T> source, System.Threading.CancellationToken cancellationToken) { throw null; }
     }
     public partial class TaskSchedulerException : System.Exception
     {

src/System.Threading.Tasks/tests/System.Runtime.CompilerServices/ConfiguredCancelableAsyncEnumerableTests.netcoreapp.cs

@@ -35,7 +35,7 @@ public void Default_EnumeratorMembers_Throws()
         [Fact]
         public void Default_WithCancellation_ConfigureAwait_NoThrow()
         {
-            ConfiguredCancelableAsyncEnumerable<int> e = TaskExtensions.WithCancellation((IAsyncEnumerable<int>)null, default);
+            ConfiguredCancelableAsyncEnumerable<int> e = ((IAsyncEnumerable<int>)null).WithCancellation(default);
             e = e.ConfigureAwait(false);
             e = e.WithCancellation(default);
             Assert.Throws<NullReferenceException>(() => e.GetAsyncEnumerator());
@@ -44,7 +44,7 @@ public void Default_WithCancellation_ConfigureAwait_NoThrow()
         [Fact]
         public void Default_ConfigureAwait_WithCancellation_NoThrow()
         {
-            ConfiguredCancelableAsyncEnumerable<int> e = TaskExtensions.ConfigureAwait((IAsyncEnumerable<int>)null, false);
+            ConfiguredCancelableAsyncEnumerable<int> e = ((IAsyncEnumerable<int>)null).ConfigureAwait(false);
             e = e.WithCancellation(default);
             e = e.ConfigureAwait(false);
             Assert.Throws<NullReferenceException>(() => e.GetAsyncEnumerator());

src/shims/ApiCompatBaseline.netcoreapp.netstandard.txt

@@ -68,4 +68,7 @@ CannotSealType : Type 'System.Linq.EnumerableExecutor' is effectively (has a pri
 MembersMustExist : Member 'System.Linq.EnumerableExecutor..ctor()' does not exist in the implementation but it does exist in the contract.
 CannotSealType : Type 'System.Linq.EnumerableQuery' is effectively (has a private constructor) sealed in the implementation but not sealed in the contract.
 MembersMustExist : Member 'System.Linq.EnumerableQuery..ctor()' does not exist in the implementation but it does exist in the contract.
-Total Issues: 59
+MembersMustExist : Member 'System.Threading.Tasks.TaskExtensions.ConfigureAwait(System.IAsyncDisposable, System.Boolean)' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'System.Threading.Tasks.TaskExtensions.ConfigureAwait<T>(System.Collections.Generic.IAsyncEnumerable<T>, System.Boolean)' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'System.Threading.Tasks.TaskExtensions.WithCancellation<T>(System.Collections.Generic.IAsyncEnumerable<T>, System.Threading.CancellationToken)' does not exist in the implementation but it does exist in the contract.
+Total Issues: 62

src/shims/ApiCompatBaseline.netcoreapp.netstandardOnly.txt

@@ -85,6 +85,9 @@ CannotMakeMemberNonVirtual : Member 'System.ComponentModel.BaseNumberConverter.C
 CannotMakeMemberNonVirtual : Member 'System.ComponentModel.BaseNumberConverter.CanConvertTo(System.ComponentModel.ITypeDescriptorContext, System.Type)' is non-virtual in the implementation but is virtual in the contract.
 CannotMakeMemberNonVirtual : Member 'System.ComponentModel.BaseNumberConverter.ConvertFrom(System.ComponentModel.ITypeDescriptorContext, System.Globalization.CultureInfo, System.Object)' is non-virtual in the implementation but is virtual in the contract.
 CannotMakeMemberNonVirtual : Member 'System.ComponentModel.BaseNumberConverter.ConvertTo(System.ComponentModel.ITypeDescriptorContext, System.Globalization.CultureInfo, System.Object, System.Type)' is non-virtual in the implementation but is virtual in the contract.
+MembersMustExist : Member 'System.Threading.Tasks.TaskExtensions.ConfigureAwait(System.IAsyncDisposable, System.Boolean)' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'System.Threading.Tasks.TaskExtensions.ConfigureAwait<T>(System.Collections.Generic.IAsyncEnumerable<T>, System.Boolean)' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'System.Threading.Tasks.TaskExtensions.WithCancellation<T>(System.Collections.Generic.IAsyncEnumerable<T>, System.Threading.CancellationToken)' does not exist in the implementation but it does exist in the contract.
 CannotSealType : Type 'System.Xml.Schema.XmlSchemaDatatype' is effectively (has a private constructor) sealed in the implementation but not sealed in the contract.
 MembersMustExist : Member 'System.Xml.Schema.XmlSchemaDatatype..ctor()' does not exist in the implementation but it does exist in the contract.
 CannotMakeMemberNonVirtual : Member 'System.Xml.Schema.XmlSchemaDatatype.TokenizedType' is non-virtual in the implementation but is virtual in the contract.
@@ -117,4 +120,4 @@ CannotSealType : Type 'System.Linq.EnumerableExecutor' is effectively (has a pri
 MembersMustExist : Member 'System.Linq.EnumerableExecutor..ctor()' does not exist in the implementation but it does exist in the contract.
 CannotSealType : Type 'System.Linq.EnumerableQuery' is effectively (has a private constructor) sealed in the implementation but not sealed in the contract.
 MembersMustExist : Member 'System.Linq.EnumerableQuery..ctor()' does not exist in the implementation but it does exist in the contract.
-Total Issues: 118
+Total Issues: 121