* @param isDirect whether to use direct transmission
     * @throws IOException if an I/O error occurs
     */
    protected abstract void doSendFragment(byte[] buf, int off, int length, boolean isDirect) throws IOException;

    /**
     * Receives a DCERPC fragment from the remote endpoint
     * @param buf the buffer to receive the fragment
     * @param isDirect whether to use direct reception

            off += fragSize;
        }
        throw new IOException();
    }

    /**
     * @param msg
     * @param in
     * @param off
     * @param isDirect
     * @return
     * @throws IOException
     * @throws DcerpcException
     * @throws NdrException
     */