isochronous endpoint I/O
thread safety
abstraction for cross-platform-ness
-fallback on /proc/bus/usb on linux
error codes
for 1.1 or future
config struct/function naming
typedef _cb or _cb_fn or _cb_t?
typedef as-is or pointers? libusb_dev_t rather than libusb_dev *?
+FP_ urb status codes