// Copyright (c) 2022 .NET Foundation and Contributors. All rights reserved.

// 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 full license information.

namespace System.Reactive.Linq;

/// <summary>

/// Provides commonly required, statically-allocated, pre-canned observables.

/// </summary>

/// <typeparam name="T">

/// The observable type.

/// </typeparam>

internal static class Observable<T>

{

/// <summary>

/// An empty observable of type <typeparamref name="T"/>.

/// </summary>

public static readonly IObservable<T> Empty = Observable.Empty<T>();

/// <summary>

/// An observable of type <typeparamref name="T"/> that never ticks a value.

/// </summary>

public static readonly IObservable<T> Never = Observable.Never<T>();

/// <summary>

/// An observable of type <typeparamref name="T"/> that ticks a single, default value.

/// </summary>

public static readonly IObservable<T> Default = Observable.Return(default(T)!);

}