Passive Mode

  Does anyone know how to use "Passive Mode" multithreading? I can't
find any of the support alluded to in the following paragraph in the
documentation at

    Passive mode
      This is the mode that requires the most advanced client, for example, a
      GUI client. On every HTTP request from the client, the library initiates
      the connection and as soon as it is ready for reading or writing, it
      returns an updated list of active socket descriptors used in the library
      to the client. When the client sees that a socket is ready for action or
      it has been interrupted, it calls a library socket-handler passing the
      socket number and what has to be done. Then the socket handler finds the
      corresponding request and executes the read, write or interrupt. As soon
      as the thread has to access the network again, the socket handler stops
      and returns the execution to the client.

  I don't see a load function which accepts a request and returns "an
updated list of active socket descriptors", nor do I see any
socket-handler functions that accept a socket and a callback. I'm
tempted to just do what HTEventLoop does, but the above seems to imply
a different model.