Класс запуска OWIN в VB.NET

Я пытаюсь создать класс запуска OWIN для проверки подлинности Azure AD, используя образец проекта от Microsoft в качестве эталона. Образец написан на C#, но проект, к которому я его адаптирую, находится на VB.NET, поэтому мне нужно преобразовать следующий C# в VB.NET:

public class Startup
{
    // The Client ID is used by the application to uniquely identify itself to Azure AD.
    string clientId = System.Configuration.ConfigurationManager.AppSettings["ClientId"];

    // RedirectUri is the URL where the user will be redirected to after they sign in.
    string redirectUri = System.Configuration.ConfigurationManager.AppSettings["RedirectUri"];

    // Tenant is the tenant ID (e.g. contoso.onmicrosoft.com, or 'common' for multi-tenant)
    static string tenant = System.Configuration.ConfigurationManager.AppSettings["Tenant"];

    // Authority is the URL for authority, composed by Azure Active Directory v2 endpoint and the tenant name (e.g. https://login.microsoftonline.com/contoso.onmicrosoft.com/v2.0)
    string authority = String.Format(System.Globalization.CultureInfo.InvariantCulture, System.Configuration.ConfigurationManager.AppSettings["Authority"], tenant);

    /// <summary>
    /// Configure OWIN to use OpenIdConnect 
    /// </summary>
    /// <param name = "app"></param>
    public void Configuration(IAppBuilder app)
    {
        app.SetDefaultSignInAsAuthenticationType(CookieAuthenticationDefaults.AuthenticationType);

        app.UseCookieAuthentication(new CookieAuthenticationOptions());
        app.UseOpenIdConnectAuthentication(
            new OpenIdConnectAuthenticationOptions
            {
                // Sets the ClientId, authority, RedirectUri as obtained from web.config
                ClientId = clientId,
                Authority = authority,
                RedirectUri = redirectUri,
                // PostLogoutRedirectUri is the page that users will be redirected to after sign-out. In this case, it is using the home page
                PostLogoutRedirectUri = redirectUri,
                Scope = OpenIdConnectScope.OpenIdProfile,
                // ResponseType is set to request the id_token - which contains basic information about the signed-in user
                ResponseType = OpenIdConnectResponseType.IdToken,
                // ValidateIssuer set to false to allow personal and work accounts from any organization to sign in to your application
                // To only allow users from a single organizations, set ValidateIssuer to true and 'tenant' setting in web.config to the tenant name
                // To allow users from only a list of specific organizations, set ValidateIssuer to true and use ValidIssuers parameter 
                TokenValidationParameters = new TokenValidationParameters()
                {
                    ValidateIssuer = false
                },
                // OpenIdConnectAuthenticationNotifications configures OWIN to send notification of failed authentications to OnAuthenticationFailed method
                Notifications = new OpenIdConnectAuthenticationNotifications
                {
                    AuthenticationFailed = OnAuthenticationFailed
                }
            }
        );
    }

    /// <summary>
    /// Handle failed authentication requests by redirecting the user to the home page with an error in the query string
    /// </summary>
    /// <param name = "context"></param>
    /// <returns></returns>
    private Task OnAuthenticationFailed(AuthenticationFailedNotification<OpenIdConnectMessage, OpenIdConnectAuthenticationOptions> context)
    {
        context.HandleResponse();
        context.Response.Redirect("/?errormessage = " + context.Exception.Message);
        return Task.FromResult(0);
    }
}

Вот мой конвертированный VB.NET:

Public Class Startup
    Private clientId As String = ConfigurationManager.AppSettings("ClientId")
    Private redirectUri As String = ConfigurationManager.AppSettings("RedirectUri")
    Shared tenant As String = ConfigurationManager.AppSettings("Tenant")
    Private authority As String = String.Format(Globalization.CultureInfo.InvariantCulture, ConfigurationManager.AppSettings("Authority"), tenant)

    Public Sub Configuration(ByVal app As IAppBuilder)
        app.SetDefaultSignInAsAuthenticationType(CookieAuthenticationDefaults.AuthenticationType)
        app.UseCookieAuthentication(New CookieAuthenticationOptions())

        app.UseOpenIdConnectAuthentication(New OpenIdConnectAuthenticationOptions With {
            .ClientId = clientId,
            .Authority = authority,
            .RedirectUri = redirectUri,
            .PostLogoutRedirectUri = redirectUri,
            .Scope = OpenIdConnectScope.OpenIdProfile,
            .ResponseType = OpenIdConnectResponseType.IdToken,
            .TokenValidationParameters = New TokenValidationParameters() With {
                .ValidateIssuer = False
            },
            .Notifications = New OpenIdConnectAuthenticationNotifications With {
                .AuthenticationFailed = OnAuthenticationFailed() '<---ERROR HERE
            }
        })
    End Sub

    Private Function OnAuthenticationFailed(ByVal context As AuthenticationFailedNotification(Of OpenIdConnectMessage, OpenIdConnectAuthenticationOptions)) As Task
        context.HandleResponse()
        context.Response.Redirect("/?errormessage = " & context.Exception.Message)
        Return Task.FromResult(0)
    End Function
End Class

Однако я получаю сообщение об ошибке в строке .AuthenticationFailed = OnAuthenticationFailed(). Ошибка говорит, что мне нужно передать параметр context, что имеет смысл, но я не понимаю, почему это не требуется в версии C# и что я должен передать в VB.NET.

Спасибо!