if (minSize <= sendBufferSize) {
            RdmaMemoryRegion region = availableSendRegions.poll();
            if (region != null) {
                region.getBuffer().clear();
                return region;
            }
        }

        // Allocate new buffer
        ByteBuffer buffer = ByteBuffer.allocateDirect(Math.max(minSize, sendBufferSize));

 */
public interface BufferCache {

    /**
     * Gets a buffer from the cache or creates a new one if the cache is empty.
     *
     * @return a buffer from the cache, or a new one
     */
    byte[] getBuffer();

    /**
     * Return a buffer to the cache
     *
     * @param buf the buffer to return to the cache for reuse
     */
    void releaseBuffer(byte[] buf);

        RdmaMemoryRegion region = provider.registerMemory(buffer, access);
        assertNotNull(region, "Memory region should not be null");
        assertEquals(buffer, region.getBuffer(), "Buffer should match");
        assertEquals(1024, region.getSize(), "Size should match buffer size");
        assertTrue(region.hasAccess(RdmaAccess.LOCAL_READ), "Should have local read access");

        if (this.state == 0) {
            bind();
        }
        final byte[] inB = this.transportContext.getBufferCache().getBuffer();
        final byte[] out = this.transportContext.getBufferCache().getBuffer();
        try {
            final NdrBuffer buf = encodeMessage(msg, out);
            final int off = sendFragments(msg, out, buf);

                        // Test allocation performance
                        long allocStart = System.nanoTime();
                        byte[] buffer = BufferCache.getBuffer();
                        long allocEnd = System.nanoTime();
                        totalAllocTime.addAndGet(allocEnd - allocStart);
                        allocations.incrementAndGet();

        boolean isDirect;
        DcerpcException de;

        if (state == 0) {
            bind();
        }

        isDirect = true;

        stub = jcifs.smb1.smb1.BufferCache.getBuffer();
        try {
            int off, tot, n;

            buf = new NdrBuffer(stub, 0);

            msg.flags = DCERPC_FIRST_FRAG | DCERPC_LAST_FRAG;
            msg.call_id = call_id++;

            alignmentBytes = 1; // Need 1 byte of padding for 2-byte alignment
        }

        // The value 0xCD should be encoded as a 16-bit value (0x00CD) in little-endian
        byte[] bufferData = buf.getBuffer();
        assertEquals((byte) 0xCD, bufferData[startIndex + alignmentBytes], "Least significant byte should be first");

    public int getTailSpace() {
        return buf.length - index;
    }

    /**
     * Returns the underlying byte buffer.
     *
     * @return the byte buffer
     */
    public byte[] getBuffer() {
        return buf;
    }

    /**
     * Aligns the buffer index to the specified boundary with a fill value.
     *
     * @param boundary the alignment boundary

    @Override
    protected void doSend(final Request request) throws IOException {

        CommonServerMessageBlock smb = (CommonServerMessageBlock) request;
        final byte[] buffer = this.getContext().getBufferCache().getBuffer();
        try {
            // synchronize around encode and write so that the ordering for SMB1 signing can be maintained
            synchronized (this.outLock) {
                final int n = smb.encode(buffer, 4);

        lenient().when(mockContext.getBufferCache()).thenReturn(mockBufferCache);

        // Setup buffer cache to return buffers for sendrecv operations
        lenient().when(mockBufferCache.getBuffer()).thenReturn(new byte[8192]);
    }

    /**
     * Helper method to create a DcerpcPipeHandle with injected mocks
     * Uses mock to avoid constructor issues while allowing real method calls
     */