Encapsulate flow descriptions inside a struct.

adsbus/flow.h

@@ -0,0 +1,17 @@
+#pragma once
+
+#include <stdint.h>
+
+struct buf;
+struct peer;
+
+typedef void (*flow_bound_socket_init)(int);
+typedef void (*flow_new)(int, void *, struct peer *);
+typedef void (*flow_get_hello)(struct buf **, void *);
+struct flow {
+	const char *name;
+	flow_bound_socket_init bound_socket_init;
+	flow_new new;
+	flow_get_hello get_hello;
+	uint32_t *ref_count;
+};