// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System;
 
namespace Microsoft.Extensions.Logging
{
    /// <summary>
    /// Scope provider that does nothing.
    /// </summary>
    internal sealed class NullExternalScopeProvider : IExternalScopeProvider
    {
        private NullExternalScopeProvider()
        {
        }
 
        /// <summary>
        /// Returns a cached instance of <see cref="NullExternalScopeProvider"/>.
        /// </summary>
        public static IExternalScopeProvider Instance { get; } = new NullExternalScopeProvider();
 
        /// <inheritdoc />
        void IExternalScopeProvider.ForEachScope<TState>(Action<object?, TState> callback, TState state)
        {
        }
 
        /// <inheritdoc />
        IDisposable IExternalScopeProvider.Push(object? state)
        {
            return NullScope.Instance;
        }
    }
}