Add mailbox setup and teardown

main.c

@@ -93,4 +93,12 @@ int main(int argc, char *argv[]) {
 		printf("#%d recipient=%d value=%d\n", i, inputs[i].recipient, inputs[i].value);
 	}
 	free(inputs);
+
+	int init_result = init_mailboxes(num_threads);
+	if (init_result != 0) {
+		printf("Failed to setup mailboxes.\n");
+		return 1;
+	}
+
+	free_mailboxes();
 }