mono/netcore/System.Private.CoreLib/shared/System/AsyncCallback.cs

// 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.

/*============================================================
**
** Interface: AsyncCallbackDelegate
**
** Purpose: Type of callback for async operations
**
===========================================================*/

namespace System
{
    public delegate void AsyncCallback(IAsyncResult ar);
}