Windows 8 and Server 2012 sport RIO, which allows you to pre-register I/O buffers once and then just use those same buffers repeatedly, avoiding the otherwise (apparently) necessary per-I/O-op buffer checks.
RIO also allows completion operations such as polling to be done entirely in user-mode, without making system calls.
(How) is this possible with Linux/Unix?
Starting with Linux Kernel 5.1 there is finally proper support with io_uring.