title: Throw exception on single FluentValidation rule failure
body: <p>Using FluentValidation, is it possible to throw an exception on a single rule failure? For example, I would like to call Validate() and for the first rule below to simply validate but the second to throw an exception if false.</p>
  
  <pre><code>RuleFor(x =&gt; x.Title)
      .NotEmpty()
      .WithMessage("Please add a title for the project");
  
  RuleFor(x =&gt; x.UserId)
      .NotEmpty()
      .WithMessage("User not supplied");
  </code></pre>
  
  <p>I'm probably trying to force FluentValidation to do something it is not designed to do. And I am aware of the ValidateAndThrow() method, but this will throw an exception on any failure.</p>