docs: public void writeTo (@Nonnull @WillNotClose final OutputStream aOS) throws IOException
    {
      // we may only need to check if this is closed if we are working with a file
      // but we should force the habit of closing whether we are working with
      // a file or memory.
      if (!m_bClosed)
        throw new IOException ("This stream is not closed");
  
      if (isInMemory ())
      {
        m_aMemoryOS.writeTo (aOS);
      }
      else
      {
        final InputStream aIS = FileHelper.getInputStream (m_aOutputFile);
        StreamHelper.copyInputStreamToOutputStream (aIS, aOS);
      }
    }