abuf_rdiscard
void abuf_rdiscard(struct abuf *, int);
abuf_rdiscard(&s->buf, n);
abuf_rdiscard(&s->buf, icnt * s->bpf);
void abuf_rdiscard(struct abuf *, int);
abuf_rdiscard(&s->mix.buf, s->round * s->mix.bpf);
abuf_rdiscard(&s->mix.buf, s->round * s->mix.bpf);
abuf_rdiscard(&s->mix.buf, s->round * s->mix.bpf);
abuf_rdiscard(&oep->obuf, oep->obuf.used);
abuf_rdiscard(&ep->obuf, n);
abuf_rdiscard(&f->slot->sub.buf, n);
abuf_rdiscard(&f->midi->obuf, n);