title: Google API SignIn HostedDomain cleanup problem
body: <p>We implement the Sign-In on iOS using the Google API in our project. Customers must have a possibility to select the HostedDomain to limit the allowed account pull to the single domain.</p>
  
  <pre><code>SignIn.SharedInstance.HostedDomain = "domainName.com";
  </code></pre>
  
  <p>works perfectly. </p>
  
  <p>The problem is when we want to Logout the user and log in it back with unrestricted HostedDomain</p>
  
  <pre><code>SignIn.SharedInstance.HostedDomain == null; // &lt;-Default Value
  </code></pre>
  
  <p>When I try to set it to </p>
  
  <pre><code>SignIn.SharedInstance.HostedDomain=string.empty;
  </code></pre>
  
  <p>I filter everything.</p>
  
  <p>When I try to set it to null </p>
  
  <pre><code>SignIn.SharedInstance.HostedDomain=null;
  </code></pre>
  
  <p>I get the exception.</p>
  
  <p>Calling:</p>
  
  <pre><code>SignIn.SharedInstance.Dispose();
  </code></pre>
  
  <p>doesn't help.</p>
  
  <p>The question is: How is possible to reset the HostedDomain filtering to the initial stage  - allow everything without of the app restart.</p>
  
  <p>Our implementation based on Xamarin iOS native, but we see the same problem in Swift or Objective-C.</p>
  
  <p>The wrapper for the Gooogle SDK we use:
  Xamarin.Google.iOS.SignIn</p>