if (c->bin != last_bin) { // then possibly write the binning index
if (save_bin != 0xffffffffu) // save_bin==0xffffffffu only happens to the first record
insert_offset(idx->index[save_tid], save_bin, save_off, last_off);
save_off = last_off;
save_bin = last_bin = c->bin;
save_tid = c->tid;
if (c->bin != last_bin) { // then possibly write the binning index
if (save_bin != 0xffffffffu) // save_bin==0xffffffffu only happens to the first record
insert_offset(idx->index[save_tid], save_bin, save_off, last_off);
save_off = last_off;
save_bin = last_bin = c->bin;
save_tid = c->tid;