libusb20_tr_open
err = libusb20_tr_open(xfer, bufsize, 1, ep_no);
err = libusb20_tr_open(pxfer0, buffsize, maxframe, endpoint);
err = libusb20_tr_open(xfer, 0, 1, endpoint);
int libusb20_tr_open(struct libusb20_transfer *xfer, uint32_t max_buf_size, uint32_t max_frame_count, uint8_t ep_no);
if ((rv = libusb20_tr_open(xfr_out, 0, 1, out_ep)) != 0)
if ((rv = libusb20_tr_open(xfr_in, 0, 1, in_ep)) != 0)
if ((rv = libusb20_tr_open(xfr_intr, 0, 1, intr_ep)) != 0)
error = libusb20_tr_open(pxfer, 1, 1, epno);
error = libusb20_tr_open(p->xfer_in, 65536 / 4, 1, in_ep);
error = libusb20_tr_open(p->xfer_out, 65536 / 4, 1, out_ep);
error = libusb20_tr_open(xfer_in, 65536, 1, in_ep);
error = libusb20_tr_open(xfer_out, 65536, 1, out_ep);