Configuring offline caching for Azure App Configuration

Program.cs

using Azure.Identity;
using Microsoft.Extensions.Configuration.AzureAppConfiguration;

namespace MusicStore.Web
{
    public class Program
    {
        ..

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .ConfigureWebHostDefaults(webBuilder => {
                    webBuilder.UseStartup<Startup>();
                })
                .ConfigureAppConfiguration((context, config) => {
                    var settings = config.Build();
                    var appConfigEndpoint = settings["AppSettings:AppConfiguration:Endpoint"];
                    var userAssignedIdentityClientId = settings["AppSettings:Identity:ClientId"];

                    if (!string.IsNullOrEmpty(appConfigEndpoint))
                    {
                        var endpoint = new Uri(appConfigEndpoint);

                        config.AddAzureAppConfiguration(options =>
                        {
                            options
                                // Use managed identity to access app configuration
                                .Connect(endpoint, new ManagedIdentityCredential(clientId: userAssignedIdentityClientId))

                                // Setup dynamic refresh
                                .ConfigureRefresh(refreshOpt =>
                                {
                                    refreshOpt.Register(key: "AppSettings:Version", refreshAll: true, label: LabelFilter.Null);
                                    refreshOpt.SetCacheExpiration(TimeSpan.FromSeconds(10));
                                })

                                // Setup offline cache
                                .SetOfflineCache(new OfflineFileCache())
                                .UseFeatureFlags();
                        });
                    }

                });
    }
}