Low level X11 programming

How to use X11 without Xlib not XCB? How draw window directly on low level?
I must use anyway window manager like Motif?
I have ridden that X11 has server-client architecture, client send via TCP/IP to port 6000 request for primitives and get replies.
Where is detailed description of it? In X11 doc is 35 directories like bigreqsproto, compositeproto, damageproto, dri2proto ...

I see that usually not using port 6000 but file (symlink) X0 in hidden directory /tmp/.X11-unix
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I begin to understand thanks to x11protocol.pdf from doc.tar.bz2 from ftp://ftp.ntua.gr/pub/X11/X.org/X11R7.7, but I don't know if is possible copy bitmap from client to server? Is request CopyArea but this copy area from on place of screen to other. Requests are small and sending big bitmaps is time consuming especially with remote servers. In other hand - memory bitmaps enable fast pixel changing, for example I read jpg from file to memory. If I have image in memory, how send it to server?