== DETAILS
Starting to implement the I/O handling on the HID driver.
The old implementation basically had a never-ending HIDRead() callback
set up, so that callback N would start the read process for invocation
N+1.
We will take the same approach here; but now that the I/O thread is
happenning on its own core, we should be able to let it run full-
throttle without impacting emulator performance.
Of course, this hinges on the callback actually running on the same
core as the syscall was initiated on.
== TESTING
Can confirm that the read_loop_callback gets invoked on the same core
that the HIDRead() was invoked on.
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