reactive/Rx.NET/Source/System.Reactive.Linq/Reactive/Internal/IEvaluatableObservable.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.Reactive
{
    interface IEvaluatableObservable<T>
    {
        IObservable<T> Eval();
    }
}