="Courier New, Courier, mono">xeh</font>. 
  Internal requests (messages that require an immediate response) are handled 
  by the internal request handler, <font face="Courier New, Courier, mono">irh</font>. 
  External requests are handled by the external request handler, <font face="Courier New, Courier, mono">xrh</font>.</p>
<p>The 'oracle' mechanism (see ask<font face="Courier New, Courier, mono">Oracle()</font> 
  and <font face="Courier New, Courier, mono">setOracle()</font>) is a protocol 
  for com