Source position: libusb.pp line 986
type libusb_transfer_flags = (
LIBUSB_TRANSFER_SHORT_NOT_OK = 1 shl 0,
LIBUSB_TRANSFER_FREE_BUFFER = 1 shl 1,
LIBUSB_TRANSFER_FREE_TRANSFER = 1 shl 2,
LIBUSB_TRANSFER_ADD_ZERO_PACKET = 1 shl 3
);