snd_seq_event_dup
err = snd_seq_event_dup(client->pool, event, &cell, !blocking || atomic,
err = snd_seq_event_dup(f->pool, event, &cell, 1, NULL, NULL); /* always non-blocking */
int snd_seq_event_dup(struct snd_seq_pool *pool, struct snd_seq_event *event,