JREC_BEGMAGIC
if (head.begmagic != JREC_BEGMAGIC) {
if (headp->begmagic != JREC_BEGMAGIC) {
while (res < bytes && rawp->begmagic == JREC_BEGMAGIC) {
if (ack.rbeg.begmagic != JREC_BEGMAGIC ||
KKASSERT(rawp->begmagic == JREC_BEGMAGIC);
rawp->begmagic = JREC_BEGMAGIC;
rawp->begmagic = JREC_BEGMAGIC;