mono/netcore/System.Private.CoreLib/shared/System/Collections/IEqualityComparer.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.

namespace System.Collections
{
    // An IEqualityComparer is a mechanism to consume custom performant comparison infrastructure
    // that can be consumed by some of the common collections.
    public interface IEqualityComparer
    {
        bool Equals(object? x, object? y);
        int GetHashCode(object obj);
    }
}