    ServerAuthContext implementation invokes secureResponse of one or more encapsulated ServerAuthModules. Modules secure
       response (sign and encrypt response, for example), and prepare response message.
   <li>Send secured response to client.
   <li>Invoke <i>cleanSubject</i> (as necessary) to clean up any authentication state in Subject(s).
 </ol>

 <p>
 A ServerAuthContext instance may be used concurrently by multiple callers.

 <p>
 Implementations of this interface are responsible for constructin