 an exception if the header does not exist)
</p></div></div><div class="top"><p class="src"><a name="v:getHB" class="def">getHB</a> ::  Message m -&gt; IO Int</p><div class="doc"><p>Get Heartbeat specification from headers
   (and throw an exception if the header does not exist
        or if its value is not numeric)
</p></div></div><div class="top"><p class="src"><a name="v:getSC" class="def">getSC</a> ::  Message m -&gt; IO (Either String <a href="Network-Mom-Stompl-Patterns-Basic.html#t:StatusCode">Statu