al dispatch
and should be marginally faster than switch statements which need to
check bounds before indexing into a table. In the performed experiments
there was no measurable difference between #1 and #3. 
Despite this the Actor scheme was picked because ...
<ul>
<li>
  The "inheritance" scheme used in #1 multiplies the number of
  times a switch has to be performed.
<li>
  It's more OO than switch statements. It frees us from having to
  assign numbers to action codes.
</ul>
<p>
This decision was made wi