/**
     * @return whether the FD is open and valid
     */
    boolean isOpen ();


    /**
     * @return whether the FD was previously open but became invalid
     */
    boolean isStale ();


    /**
     * @param type
     * @return unwrapped instance
     */
    <T extends SmbPipeHandle> T unwrap ( Class<T> type );

            return sess.getSessionKey();
        }
    }


    /**
     * {@inheritDoc}
     *
     * @see jcifs.SmbPipeHandle#isStale()
     */
    @Override
    public boolean isStale () {
        return !this.open || ( this.handle != null && !this.handle.isValid() );
    }


    @Override

     */
    @Override
    protected int doSendReceiveFragment ( byte[] buf, int off, int length, byte[] inB ) throws IOException {
        if ( this.handle.isStale() ) {
            throw new IOException("DCERPC pipe is no longer open");
        }

        int have = this.handle.sendrecv(buf, off, length, inB, getMaxRecv());

        int fraglen = Encdec.dec_uint16le(inB, 8);

                return send0(loc, request, response, params);
            }
            catch ( SmbException smbe ) {
                // Retrying only makes sense if the invalid parameter is an tree id. If we have a stale file descriptor
                // retrying make no sense, as it will never become available again.
                if ( params.contains(RequestParam.NO_RETRY)