/**
     * Cumulates content of <tt>in</tt> into internal buffer and forwards
     * decoding request to
     * {@link #doDecode(IoSession, IoBuffer, ProtocolDecoderOutput)}.
     * <tt>doDecode()</tt> is invoked repeatedly until it returns <tt>false</tt>
     * and the cumulative buffer is compacted after decoding ends.
     *
     * @throws IllegalStateException
     *             if your <tt>doDecode()</tt> returned <tt>true</tt> not
     *             consuming the cumulative buffer.
     */
    public void decode(IoSession session, IoBuffer in, ProtocolDecoderOutput out) throws Exception {
//        if (!session.getTransportMetadata().hasFragmentation()) {
            while (in.hasRemaining()) {
                if (!doDecode(session, in, out)) {
                    break;
                }
            }

//            return;
//        }

        boolean usingSessionBuffer = true;
        IoBuffer buf = (IoBuffer) session.getAttribute(BUFFER);
        // If we have a session buffer, append data to that; otherwise
        // use the buffer read from the network directly.
        if (buf != null) {
            boolean appended = false;
            // Make sure that the buffer is auto-expanded.
            if (buf.isAutoExpand()) {
                try {
                    buf.put(in);
                    appended = true;
                } catch (IllegalStateException e) {
                    // A user called derivation method (e.g. slice()),
                    // which disables auto-expansion of the parent buffer.
                } catch (IndexOutOfBoundsException e) {
                    // A user disabled auto-expansion.
                }
            }

            if (appended) {
                buf.flip();
            } else {
                // Reallocate the buffer if append operation failed due to
                // derivation or disabled auto-expansion.
                buf.flip();
                IoBuffer newBuf = IoBuffer.allocate(buf.remaining() + in.remaining()).setAutoExpand(true);
                newBuf.order(buf.order());
                newBuf.put(buf);
                newBuf.put(in);
                newBuf.flip();
                buf = newBuf;

                // Update the session attribute.
                session.setAttribute(BUFFER, buf);
            }
        } else {
            buf = in;
            usingSessionBuffer = false;
        }

        for (;;) {
            int oldPos = buf.position();
            boolean decoded = doDecode(session, buf, out);
            if (decoded) {
                if (buf.position() == oldPos) {
                    throw new IllegalStateException("doDecode() can't return true when buffer is not consumed.");
                }

                if (!buf.hasRemaining()) {
                    break;
                }
            } else {
                break;
            }
        }

        // if there is any data left that cannot be decoded, we store
        // it in a buffer in the session and next time this decoder is
        // invoked the session buffer gets appended to
        if (buf.hasRemaining()) {
            if (usingSessionBuffer && buf.isAutoExpand()) {
                buf.compact();
            } else {
                storeRemainingInSession(buf, session);
            }
        } else {
            if (usingSessionBuffer) {
                removeSessionBuffer(session);
            }
        }
    }