docs: private final void expand_array()
    {
  //    if (tc.isEntryEnabled())
  //      SibTr.entry(tc, "expand_array");
  
      int length = m_array.length;
      Object[] m_new = new Object[length*2];
      System.arraycopy(m_array, m_head, m_new, m_head, length-m_head);
      System.arraycopy(m_array, 0, m_new, length, m_tail);
      m_tail += length;
      m_array = m_new;
  
  //    if (tc.isEntryEnabled())
  //      SibTr.exit(tc, "expand_array");
    }