usbd_transfer_pending
if (!usbd_transfer_pending(xfer))
error = usbd_transfer_pending(f->fs_xfer[pstall->ep_index]);
if (usbd_transfer_pending(xfer)) {
} else if (usbd_transfer_pending(xfer)) {
if (usbd_transfer_pending(xfer)) {
while (usbd_transfer_pending(sc->xfer[sc->state])) {
while (usbd_transfer_pending(sc->xfer[0]))
while (usbd_transfer_pending(xfer)) {
while (usbd_transfer_pending(xfer) ||
uint8_t usbd_transfer_pending(struct usb_xfer *xfer);