Sample code to Sign up Cognito UserPool with C# (not Unity or Xamarin)

SignUpCognitoUserPoolSample.cs

using Amazon;
using Amazon.CognitoIdentityProvider.Model;
using System.Threading.Tasks;

public class SignUpCognitoUserPoolSample
{
    public async Task SignupCognitoUserIntoUserPoolAsync()
    {
        // Identify your Cognito UserPool Provider
        using(var provider = new Amazon.CognitoIdentityProvider.AmazonCognitoIdentityProviderClient(RegionEndpoint.USEast1))
        {
            // 2016/6/22 : As there are still bug with SecretHash, do not create UserPool with Client Secret enabled. http://stackoverflow.com/questions/37438879/resolve-unable-to-verify-secret-hash-for-client-in-amazon-cognito-userpools
            // Sign up new User into your Cognito User Pool
            var signup = await provider.SignUpAsync(new SignUpRequest
            {
                ClientId = "<YOUR USER POOL APPS CLIENT ID>",
                Username = "<YOUR USERNAME TO REGISTER INTO USER POOL>",
                Password = "<YOUR USERPASSWORD TO REGISTER INTO USER POOL>",,
                UserAttributes = new List<Amazon.CognitoIdentityProvider.Model.AttributeType>
                {
                    // INPUT ANY ATTRIBUTES TO REGISTER
                    // Must include Email and Phone, if MFA is enabled
                    new AttributeType
                    {
                        Name = "email",
                        Value = "[email protected]",
                    },
                    new AttributeType
                    {
                        Name = "phone_number",
                        Value = "<PHONE NUMBER WITH COUNTRY CODE. ex: +810311111111>",
                    }
                }
            });
            signup.Dump();
        }
    }
}

After SignUp, how can i UpdateAttributes of Logged-In user? i can not find userPool.getCurrentUser(); in .Net SDK, then how can i get current user and update his attributes in C#.