monstrous things allocated in memory that you just have to "know" are
of a certain structure. In this case, we used `xcb_screen_next` to
say that we want the first (and all) screens attached to our current
X11 session. And we used
`xcb_setup_roots_iterator(xcb_get_setup(connection))` to initialize
our iterator to our connection object in local memory.
Other things we've learned along the way: the file description that
represents our connection can be a TCP/IP socket or a Unix Domain
socket (a filesystem socket, named or not), and the only way to know
which is to find if there's a hostname before the colon ':' in the
display name of the server. Not sure how that's going to work.
Also, found a really good reference: [Basic Graphics Tutorial with
XCB](https://www.x.org/releases/X11R7.6/doc/libxcb/tutorial/index.html).
It doesn't cover our specific use-case, but it's worth looking into.
