PM> Install-Package Microsoft.AspNet.Identity.Samples -Pre

public class EmailService : IIdentityMessageService
{
    public Task SendAsync(IdentityMessage message)
    {
        // Plug in your email service here to send an email.
        return Task.FromResult(0);
    }
}

public class SmsService : IIdentityMessageService
{
    public Task SendAsync(IdentityMessage message)
    {
        // Plug in your sms service here to send a text message.
        return Task.FromResult(0);
    }
}

public class ApplicationDbInitializer 
    : DropCreateDatabaseIfModelChanges<ApplicationDbContext> 
{
    protected override void Seed(ApplicationDbContext context) {
        InitializeIdentityForEF(context);
        base.Seed(context);
    }

    //Create User=Admin@Admin.com with password=Admin@123456 in the Admin role        
    public static void InitializeIdentityForEF(ApplicationDbContext db) 
    {
        var userManager = 
           HttpContext.Current.GetOwinContext().GetUserManager<ApplicationUserManager>();
        
        var roleManager = 
            HttpContext.Current.GetOwinContext().Get<ApplicationRoleManager>();

        const string name = "admin@admin.com";
        const string password = "Admin@123456";
        const string roleName = "Admin";

        //Create Role Admin if it does not exist
        var role = roleManager.FindByName(roleName);

        if (role == null) {
            role = new IdentityRole(roleName);
            var roleresult = roleManager.Create(role);
        }

        var user = userManager.FindByName(name);

        if (user == null) {
            user = new ApplicationUser { UserName = name, Email = name };
            var result = userManager.Create(user, password);
            result = userManager.SetLockoutEnabled(user.Id, false);
        }

        // Add user admin to Role Admin if not already added
        var rolesForUser = userManager.GetRoles(user.Id);

        if (!rolesForUser.Contains(role.Name)) {
            var result = userManager.AddToRole(user.Id, role.Name);
        }
    }
}

[HttpPost]
[AllowAnonymous]
[ValidateAntiForgeryToken]
public async Task<ActionResult> Register(RegisterViewModel model)
{
    if (ModelState.IsValid)
    {
        var user = new ApplicationUser { UserName = model.Email, Email = model.Email };
        var result = await UserManager.CreateAsync(user, model.Password);

        if (result.Succeeded)
        {
            var code = await UserManager.GenerateEmailConfirmationTokenAsync(user.Id);

            var callbackUrl = Url.Action(
                "ConfirmEmail", 
                "Account", 
                new { userId = user.Id, code = code }, 
                protocol: Request.Url.Scheme);

            await UserManager.SendEmailAsync(
                user.Id, 
                "Confirm your account", 
                "Please confirm your account by clicking this link: <a href=\"" 
                + callbackUrl + "\">link</a>");

            ViewBag.Link = callbackUrl;

            return View("DisplayEmail");
        }
        AddErrors(result);
    }

    // If we got this far, something failed, redisplay form
    return View(model);
}

public static ApplicationUserManager Create(
    IdentityFactoryOptions<ApplicationUserManager> options, 
    IOwinContext context)
{
    var manager = new ApplicationUserManager(
        new UserStore<ApplicationUser>(
            context.Get<ApplicationDbContext>()));

    // Configure validation logic for usernames
    manager.UserValidator = new UserValidator<ApplicationUser>(manager)
    {
        AllowOnlyAlphanumericUserNames = false,
        RequireUniqueEmail = true
    };

    // Configure validation logic for passwords
    manager.PasswordValidator = new PasswordValidator
    {
        RequiredLength = 6, 
        RequireNonLetterOrDigit = true,
        RequireDigit = true,
        RequireLowercase = true,
        RequireUppercase = true,
    };

    // Configure user lockout defaults
    manager.UserLockoutEnabledByDefault = true;
    manager.DefaultAccountLockoutTimeSpan = TimeSpan.FromMinutes(5);
    manager.MaxFailedAccessAttemptsBeforeLockout = 5;

    // Register two factor authentication providers. This application 
    // uses Phone and Emails as a step of receiving a code for verifying the user
    // You can write your own provider and plug in here.
    manager.RegisterTwoFactorProvider(
        "PhoneCode", 
        new PhoneNumberTokenProvider<ApplicationUser>
    {
        MessageFormat = "Your security code is: {0}"
    });

    manager.RegisterTwoFactorProvider(
        "EmailCode", 
        new EmailTokenProvider<ApplicationUser>
    {
        Subject = "SecurityCode",
        BodyFormat = "Your security code is {0}"
    });

    manager.EmailService = new EmailService();
    manager.SmsService = new SmsService();

    var dataProtectionProvider = options.DataProtectionProvider;

    if (dataProtectionProvider != null)
    {
        manager.UserTokenProvider = 
            new DataProtectorTokenProvider<ApplicationUser>(
                dataProtectionProvider.Create("ASP.NET Identity"));
    }

    return manager;
}

manager.EmailService = new EmailService();
manager.SmsService = new SmsService();

// Register two factor authentication providers. This application 
// uses Phone and Emails as a step of receiving a code for verifying the user
// You can write your own provider and plug in here.
manager.RegisterTwoFactorProvider(
    "PhoneCode", 
    new PhoneNumberTokenProvider<ApplicationUser>
{
    MessageFormat = "Your security code is: {0}"
});

manager.RegisterTwoFactorProvider(
    "EmailCode", 
    new EmailTokenProvider<ApplicationUser>
    {
        Subject = "SecurityCode",
        BodyFormat = "Your security code is {0}"
    });

public class EmailService : IIdentityMessageService
{
    public Task SendAsync(IdentityMessage message)
    {
        // Credentials:
        var credentialUserName = "yourAccount@outlook.com";
        var sentFrom = "yourAccount@outlook.com";
        var pwd = "yourApssword";

        // Configure the client:
        System.Net.Mail.SmtpClient client = 
            new System.Net.Mail.SmtpClient("smtp-mail.outlook.com");

        client.Port = 587;
        client.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network;
        client.UseDefaultCredentials = false;

        // Creatte the credentials:
        System.Net.NetworkCredential credentials = 
            new System.Net.NetworkCredential(credentialUserName, pwd);

        client.EnableSsl = true;
        client.Credentials = credentials;

        // Create the message:
        var mail = 
            new System.Net.Mail.MailMessage(sentFrom, message.Destination);

        mail.Subject = message.Subject;
        mail.Body = message.Body;

        // Send:
        return client.SendMailAsync(mail);
    }
}

public class EmailService : IIdentityMessageService
{
    public Task SendAsync(IdentityMessage message)
    {
        // Credentials:
        var sendGridUserName = "yourSendGridUserName";
        var sentFrom = "whateverEmailAdressYouWant";
        var sendGridPassword = "YourSendGridPassword";

        // Configure the client:
        var client = 
            new System.Net.Mail.SmtpClient("smtp.sendgrid.net", Convert.ToInt32(587));

        client.Port = 587;
        client.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network;
        client.UseDefaultCredentials = false;

        // Creatte the credentials:
        System.Net.NetworkCredential credentials = 
            new System.Net.NetworkCredential(credentialUserName, pwd);

        client.EnableSsl = true;
        client.Credentials = credentials;

        // Create the message:
        var mail = 
            new System.Net.Mail.MailMessage(sentFrom, message.Destination);

        mail.Subject = message.Subject;
        mail.Body = message.Body;

        // Send:
        return client.SendMailAsync(mail);
    }
}

PM> Install-Package Twilio

public class SmsService : IIdentityMessageService
{
    public Task SendAsync(IdentityMessage message)
    {
        string AccountSid = "YourTwilioAccountSID";
        string AuthToken = "YourTwilioAuthToken";
        string twilioPhoneNumber = "YourTwilioPhoneNumber";

        var twilio = new TwilioRestClient(AccountSid, AuthToken);

        twilio.SendSmsMessage(twilioPhoneNumber, message.Destination, message.Body); 

        // Twilio does not return an async Task, so we need this:
        return Task.FromResult(0);
    }
}

if (result.Succeeded)
{
    var code = await UserManager.GenerateEmailConfirmationTokenAsync(user.Id);
    var callbackUrl = 
        Url.Action("ConfirmEmail", "Account", 
            new { userId = user.Id, code = code }, protocol: Request.Url.Scheme);

    await UserManager.SendEmailAsync(user.Id, "Confirm your account", 
        "Please confirm your account by clicking this link: <a href=\"" + callbackUrl + "\">link</a>");

    // This should not be deployed in production:
    ViewBag.Link = callbackUrl;

    return View("DisplayEmail");
}

AddErrors(result);

@{
    ViewBag.Title = "DEMO purpose Email Link";
}

<h2>@ViewBag.Title.</h2>

<p class="text-info">
    Please check your email and confirm your email address.
</p>

<p class="text-danger">
    For DEMO only: You can click this link to confirm the email: <a href="@ViewBag.Link">link</a>
    Please change this code to register an email service in IdentityConfig to send an email.
</p>

[AllowAnonymous]
public async Task<ActionResult> VerifyCode(string provider, string returnUrl)
{
    // Require that the user has already logged in via username/password or external login
    if (!await SignInHelper.HasBeenVerified())
    {
        return View("Error");
    }

    var user = 
        await UserManager.FindByIdAsync(await SignInHelper.GetVerifiedUserIdAsync());

    if (user != null)
    {
        ViewBag.Status = 
            "For DEMO purposes the current " 
            + provider 
            + " code is: " 
            + await UserManager.GenerateTwoFactorTokenAsync(user.Id, provider);
    }

    return View(new VerifyCodeViewModel { Provider = provider, ReturnUrl = returnUrl });
}

@model IdentitySample.Models.VerifyCodeViewModel

@{
    ViewBag.Title = "Enter Verification Code";
}

<h2>@ViewBag.Title.</h2>

@using (Html.BeginForm("VerifyCode", "Account", new { ReturnUrl = Model.ReturnUrl }, FormMethod.Post, new { @class = "form-horizontal", role = "form" })) {
    @Html.AntiForgeryToken()
    @Html.ValidationSummary("", new { @class = "text-danger" })
    @Html.Hidden("provider", @Model.Provider)
    <h4>@ViewBag.Status</h4>
    <hr />

    <div class="form-group">
        @Html.LabelFor(m => m.Code, new { @class = "col-md-2 control-label" })
        <div class="col-md-10">
            @Html.TextBoxFor(m => m.Code, new { @class = "form-control" })
        </div>
    </div>

    <div class="form-group">
        <div class="col-md-offset-2 col-md-10">
            <div class="checkbox">
                @Html.CheckBoxFor(m => m.RememberBrowser)
                @Html.LabelFor(m => m.RememberBrowser)
            </div>
        </div>
    </div>

    <div class="form-group">
        <div class="col-md-offset-2 col-md-10">
            <input type="submit" class="btn btn-default" value="Submit" />
        </div>
    </div>
}

public struct Statement
{
    public int Id { get; }
    public string Description { get; }
    public Statement(int id, string description) => (Id, Description) = (id, description);
    public override string ToString() => Description;
}

public static async Task<IEnumerable<Statement>> GetStatements(bool error)
{
    if (error)
    {
       throw new Exception("Oops, we messed up 😬");
    }

    await Task.Delay(1000); //Simulate waiting for data to come through. 

    yield return new Statement(1, "C# is cool!");
    yield return new Statement(2, "C# orginally named COOL.");
    yield return new Statement(3, "More examples...");
}

The body of 'AsyncStreams.GetStatements(bool)' cannot be an iterator block because
'Task<IEnumerable<AsyncStreams.Statement>>' is not an iterator interface type (CS1624)

static async IAsyncEnumerable<Statement> GetStatements(bool error)

static async IAsyncEnumerable<Statement> GetStatementsAsync(bool error)
{
    await foreach (var statement in GetStatements(error))
    {
      await Task.Delay(1000);
      yield return statement;
    }
}

using System.Threading;

namespace System.Collections.Generic
{
    public interface IAsyncEnumerable<out T>
    {
        IAsyncEnumerator<T> GetAsyncEnumerator(CancellationToken cancellationToken = default);
    }

    public interface IAsyncEnumerator<out T> : IAsyncDisposable
    {
        T Current { get; }

        ValueTask<bool> MoveNextAsync();
    }
}

namespace System
{
    public interface IAsyncDisposable
    {
        ValueTask DisposeAsync();
    }
}

public class AwaitUsingTest : IAsyncDisposable
{
   public async ValueTask DisposeAsync()
   {
     await Task.CompletedTask;
   }

   public void Dummy() { }
}

async Task FooBar()
{
   await using var test = new AwaitUsingTest();
   test.Dummy();
}

The conclusion of the analysis:
C# Wasm AOT still has a long way to become a general and performant client side web programming platform. Note: The usage of the Uno.Wasm.Bootstrap toolchain may have affected the performance of some of the benchmarks. Thus, this analysis should not be regarded as a benchmark of the finalized product. However, note that the Uno platform is using ".NET 6 WebAssembly Mixed mode AOT/Interpreter" (source). 

1. Improving the development experience when using popular JavaScript libraries
2. Adding support for new JavaScript ECMAScript 2015 (also known as ES2015 and formerly ES6) language and web browser APIs
3. Increasing your productivity in complex JavaScript code bases

Use Rust or C#, abandon C++: Five Eyes agencies warn about memory safety in programming languages