code: public final int size()
    {
      if (tc.isEntryEnabled())
        SibTr.entry(tc, "size");
      int result = (m_tail >= m_head) ? (m_tail - m_head) : (m_array.length - m_head + m_tail);
      if (tc.isEntryEnabled())
        SibTr.exit(tc, "size", new Integer(result));
      return result;
    }
docs: Return the number of elements in the queue.
  
  @return the number of elements in the queue.