reactive/Ix.NET/Source/System.Linq.Async/System/Runtime/CompilerServices/EnumeratorCancellationAttribute.cs

#if !BCL_HAS_ENUMERATOR_CANCELLATION

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

namespace System.Runtime.CompilerServices
{
    [AttributeUsage(AttributeTargets.Parameter, Inherited = false)]
    public sealed class EnumeratorCancellationAttribute : Attribute
    {
    }
}

#endif