title: Implement the GetClientValidationRules from Remote Validation
body: <p><strong>Remote validation is client side validation. I need server side validation.</strong></p>
  
  <p>I do not want to call to go to my controller's action method on the http post wether user xyz already exists or not and set then the Modelstate with an error on the username key.</p>
  
  <p>I want to implement the server validation in an Inheritet Attribute from RemoteAttribute:</p>
  
  <pre><code>public class Test : RemoteAttribute
      {
          protected override ValidationResult IsValid(object value, ValidationContext validationContext)
          {
              return _service.UserExists(value);
          }
      }
  </code></pre>
  
  <p>Is this correctly implemented? Does this implementation affect the client side validation in any way?</p>