r><tr><td class="src"><a name="v:HeaderX" class="def">HeaderX</a> String String</td><td class="doc"><p>Error on Header identified by the first String
</p></td></tr><tr><td class="src"><a name="v:MissingHbX" class="def">MissingHbX</a> String</td><td class="doc"><p>Thrown on missing heartbeat 
   (after tolerance of 10 missing heartbeats)
</p></td></tr><tr><td class="src"><a name="v:UnacceptableHbX" class="def">UnacceptableHbX</a> Int</td><td class="doc"><p>Heartbeat proposed by registry
   out of acceptable 