title: how to check availablity of wcf service client for callback?
body: <p>I've implemented pub/sub framework using ASP.NET, WCF Service with net.tcp binding. I hosted wcf service on IIS7.5. My code was developed under VS2010, Windows7.</p>
  
  <p>My demo application is working fine but I just want to handle the error exception when my wcf service callback to client.</p>
  
  <p>So far, my WCF Service or ASP.NET did not throw any error to screen at all.</p>
  
  <p>here is my step of testing:</p>
  
  <ol>
  <li><p>started service</p></li>
  <li><p>opened 2 IE (e.g. UserA and UserB)</p></li>
  <li><p>both User subscribed to WCF Service</p></li>
  <li><p>closed UserB (closed IE of B)</p></li>
  <li><p>tried to send msg from UserA to UserB</p></li>
  <li><p>UserA could send msg to B but no error was appeared</p></li>
  </ol>
  
  <p>I expected that it should be some error appear to my face but no...</p>
  
  <p>please suggest me how to handle this case?</p>
  
  <p>Thank you</p>