heap_for_each
int heap_for_each(heap_context, heap_for_each_func, void *);
(void) heap_for_each(ctx->timers, print_timer, (void *)ctx);
(void) heap_for_each(ctx->timers, print_timer, (void *)ctx);
(void) heap_for_each(ctx->timers, print_timer, (void *)ctx);
(void) heap_for_each(ctx->timers, free_timer, NULL);