text: #include <stdlib.h>
  #include "list.h"
  #include "queue.h"
  
  int queue_enqueue(Queue *queue, const void *data)
  {
      return list_ins_next(queue, list_tail(queue), data);
  }
  
  int queue_dequeue(Queue *queue, void **data)
  {
      return list_rem_next(queue, NULL, data);
  }
  