We want to call socket() with the parameters provided by getaddrinfo, so we
can’t addd the fd into the poller immediately. We need to wait the
connection attempt, and then the SocketHandler can call add_socket_handler
itself, if the connection succeeds, or is in progress.
(that is, the read/write/connect/etc)
Because this code is actually common for both the IrcClient and
XmppComponent class. These two classes have to implement some higher level
callbacks (parsing the data provided in the buffers, doing stuff when the
connection is done) instead of doing the read/write/connect low level
things.
Florent Le Coz