Using Umbraco Contour in an anonymous load balanced scenario (v7.3+)

## ContourInAnonymousLoadBalancing.cs
public class ContourFormRefreshPayload
{
    public Guid Id { get; set; }
}

public class ContourFormCacheRefresher : JsonCacheRefresherBase<ContourFormCacheRefresher>
{
    public static string Id = "AA2970FD-8785-42C2-A289-A7A6614CAE45";
    protected override ContourFormCacheRefresher Instance => this;
    public override Guid UniqueIdentifier => new Guid(Id);
    public override string Name => "Clears Contour form cache";

    public override void Refresh(string json)
    {
        // ignore the payload for now - we're just wiping the form cache completely
        LogHelper.Info<ContourFormCacheRefresher>(() => "Resaving Contour form because of distributed cache instruction");
        Umbraco.Forms.Core.Services.CacheService.ClearAllCache();
    }

    internal static ContourFormRefreshPayload[] DeserializeFromJsonPayload(string json)
    {
        var serializer = new JavaScriptSerializer();
        return serializer.Deserialize<ContourFormRefreshPayload[]>(json);
    }

    internal static string SerializeToJsonPayload(params ContourFormRefreshPayload[] payloads)
    {
        var serializer = new JavaScriptSerializer();
        var json = serializer.Serialize(payloads);
        return json;
    }
}

public class ContourFormSync : ApplicationEventHandler
{
    protected override void ApplicationStarted(UmbracoApplicationBase umbracoApplication,
        ApplicationContext applicationContext)
    {
        // listen to contour forms being saved
        Umbraco.Forms.Data.Storage.FormStorage.FormCreated += DistributeCacheInstruction;
        Umbraco.Forms.Data.Storage.FormStorage.FormUpdated += DistributeCacheInstruction;
    }

    internal static void DistributeCacheInstruction(object sender, FormEventArgs e)
    {
        var refresherGuid = Guid.Parse(ContourFormCacheRefresher.Id);
        var payload = ContourFormCacheRefresher.SerializeToJsonPayload(new ContourFormRefreshPayload {Id = e.Form.Id});
        DistributedCache.Instance.RefreshByJson(refresherGuid, payload);
    }
}