
<li><tt>step</tt>: 
<a href="http://lua-users.org/wiki/FiltersSourcesAndSinks">LTN12</a> 
pump step function used to pass data from the
server to the sink. Defaults to the LTN12 <tt>pump.step</tt> function;
<li><tt>create</tt>: An optional function to be used instead of
<a href=tcp.html#socket.tcp><tt>socket.tcp</tt></a> when the communications socket is created. 
</ul>

<p class=return>
Both functions return 1 if successful, or <b><tt>nil</tt></b> and an error
message describing the reason for failure.
</