Custom Configuration Source returning instance of IConfigurationProvider implementation

CustomConfigurationSource.cs

using System;

using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;

namespace CustomConfigProviderExample.CustomConfigProvider
{
    public class CustomConfigurationSource : IConfigurationSource
    {
        private readonly Action<DbContextOptionsBuilder> _optionsAction;

        public CustomConfigurationSource(Action<DbContextOptionsBuilder> optionsAction)
        {
            _optionsAction = optionsAction;
        }

        public IConfigurationProvider Build(IConfigurationBuilder builder)
        {
            return new CustomConfigurationProvider(_optionsAction);
        }
    }
}