title: CFMessagePortInvalidationCallBack has no context info for remote ports
body: <p>When creating local ports with CFMessagePortCreateLocal you can specify context info (void *).  This is useful for pointing to an Objective-C class instance.  With CFMessagePortCreateRemote you can not specify context info.  If you wish to monitor when a remote port is invalidated via the callback specified with CFMessagePortSetInvalidationCallBack you don't have that info available in the callback.  Is there a work-around besides using a static variable?  </p>
  
  <p>I may have an unknown number of remote ports connected to separate processes.</p>