def start_subsystem(self, name, transport, channel):
pass<EOL>
Process an ssh subsystem in server mode.  This method is called on a
new object (and in a new thread) for each subsystem request.  It is
assumed that all subsystem logic will take place here, and when the
subsystem is finished, this method will return.  After this method
returns, the channel is closed.

The combination of C{transport} and C{channel} are unique; this handler
corresponds to exactly one L{Channel} on one L{Transport}.

@note: It is the responsibility of this method to exit if the
    underlying L{Transport} is closed.  This can be done by checking
    L{Transport.is_active} or noticing an EOF
    on the L{Channel}.  If this method loops forever without checking
    for this case, your python interpreter may refuse to exit because
    this thread will still be running.

@param name: name of the requested subsystem.
@type name: str
@param transport: the server-mode L{Transport}.
@type transport: L{Transport}
@param channel: the channel associated with this subsystem request.
@type channel: L{Channel}