bool next_send_less_than(void *user_data, pheap_node_id_t a, pheap_node_id_t b);
void create_send(send_t *sleeping_sends, pheap_t *sleeps_heap,
uint32_t timestamp, u16_t seq);
bool next_send_less_than(void *user_data, pheap_node_id_t a, pheap_node_id_t b);
void create_send(send_t *sleeping_sends, pheap_t *sleeps_heap,
uint32_t timestamp, u16_t seq);