Partial key rotation implementation using the Key Vault config provider

KeyProvider.cs

using Microsoft.Extensions.Configuration;

namespace Example
{
    public interface IKeyProvider
    {
        string GetKey();

        void SwitchKey();
    }

    public class KeyProvider
    {
        public KeyProvider(IConfigurationRoot config)
        {
            _config = config;
        }

        private IConfigurationRoot _config;
        private bool usePrimaryKey = true;

        
        string GetKey()
        {
            return usePrimaryKey ? _config["ServiceKey1"] : _config["ServiceKey2"];
        }

        void SwitchKey()
        {
            usePrimaryKey = !usePrimaryKey;
        }
    }
}

Program.cs

using System;
using Microsoft.AspNetCore;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Configuration.AzureKeyVault;

namespace Example
{
    public class Program
    {
        public static void Main(string[] args)
        {
            CreateWebHostBuilder(args).Build().Run();
        }

        public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
            WebHost.CreateDefaultBuilder(args)
                .UseStartup<Startup>()
                .ConfigureAppConfiguration((context, configBuilder) =>
                {                    
                    var config = configBuilder.Build();                       
                    configBuilder.AddAzureKeyVault(new AzureKeyVaultConfigurationOptions
                    {
                        Vault = config["KeyVaultUrl"],
                        ReloadInterval = TimeSpan.FromMinutes(10)
                    });
                });
    }
}