reactive/AsyncRx.NET/System.Reactive.Bcl/System/IAwaitable.cs

// 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. 

namespace System
{
    public interface IAwaitable
    {
        IAwaiter GetAwaiter();
    }

    public interface IAwaitable<T>
    {
        IAwaiter<T> GetAwaiter();
    }
}