ring_buffer_iter_peek
ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts);
EXPORT_SYMBOL_GPL(ring_buffer_iter_peek);
event = ring_buffer_iter_peek(buf_iter, ts);
while (ring_buffer_iter_peek(buf_iter, &ts)) {
event = ring_buffer_iter_peek(ring_iter, NULL);