--- /dev/null
+#ifndef SENDS_H
+#define SENDS_H
+
+#include "pico/cyw43_arch.h"
+#include "pico/util/pheap.h"
+
+typedef struct {
+ uint32_t timestamp;
+ u16_t seq;
+ u8_t send_count;
+} send_t;
+
+uint32_t next_send(send_t *s);
+
+bool next_send_less_than(void *user_data, pheap_node_id_t a, pheap_node_id_t b);
+
+#endif