[libmicrohttpd] Connection not represented by a file descriptor

[Tomas Heran]

Hello.

I've recently started evaluating libmicrohttpd for purposes of my
project and while I like very much what I've seen so far there are
specific requirements imposed by my execution environment which
make integrating MHD HTTP server a little challenging.

Namely:

- The program handles its connections independently from MHD (listening,
  accepting new client connections and spawning threads to handle the
  client connections, etc.)

- The connections are presented to the rest of the program as
  "objects", i.e. structures containing file descriptors which
  are not accessible from the client handling code (furthermore,
  even if the low-level fds were accessible, they aren't always
  sockets)

If I eventually decided to use MHD for my project, I'd have to
introduce to MHD a special kind of connection that is represented by a
set of functions for reading, writing, selecting/polling, closing etc.
and an "ID" to be able to find the particular "stream" that the
functions need to operate on.

While understanding this may be very specific to my project and not too
interesting for many others, I'd still like to know whether you'd be
interested in accepting a patch that implements such kind of
connections? My intention would be to work with the community to
introduce a suitably generic/abstract representation that would
maximize re-use for other similar use cases.

Please let me know.

Thank you,
Tomas Heran