rb_fix_abs_ts
delta = rb_fix_abs_ts(delta, ts);
ts = rb_fix_abs_ts(delta, ts);
delta = rb_fix_abs_ts(delta, cpu_buffer->read_stamp);
delta = rb_fix_abs_ts(delta, iter->read_stamp);
*ts = rb_fix_abs_ts(*ts, reader->page->time_stamp);
*ts = rb_fix_abs_ts(*ts, iter->head_page->page->time_stamp);
return rb_fix_abs_ts(ts, cpu_buffer->tail_page->page->time_stamp);