class type transport_channel_type =object..end
method setup_e : Unix.file_descr ->
       channel_binding_id ->
       float ->
       exn ->
       string ->
       int ->
       Unixqueue.event_system -> Uq_engines.multiplex_controller Uq_engines.enginesetup fd cb tmo tmo_x host port esys: Create or configure a communication
      circuit over the file descriptor fd that can be driven by the
      returned multiplex controller object.
      tmo is the timeout. After inactivity the  exception tmo_x must be
      raised.
      host is the name of the machine to connect to. port is the port
      number. The descriptor fd is already connected to this port, directly
      or via a proxy.
method continue : Unix.file_descr ->
       channel_binding_id ->
       float ->
       exn ->
       string -> int -> Unixqueue.event_system -> Uq_engines.multiplex_controllercontinue is called when an already established circuit needs to
      be continued.
      Note that the event system can be different now.