verify(cfg, times(1)).getMaximumBufferSize();
        verifyNoMoreInteractions(cfg);

        // When cache is empty, getBuffer allocates a new buffer with configured size
        byte[] buf = impl.getBuffer();
        assertNotNull(buf, "getBuffer should never return null");
        assertEquals(5, buf.length, "Newly allocated buffer length should match config maximum size");
    }

            cache.getBuffer();
            cache.releaseBuffer(new byte[1024]);
        }, "All BufferCache interface methods should be callable");
    }

    @Test
    @DisplayName("getBuffer should return non-null byte array")
    void testGetBufferContract() {
        // Given
        byte[] expectedBuffer = new byte[1024];
        when(mockBufferCache.getBuffer()).thenReturn(expectedBuffer);

        }

        return new byte[bufferSize];
    }

    static void getBuffers(final SmbComTransaction req, final SmbComTransactionResponse rsp) {
        req.txn_buf = getBuffer();
        rsp.txn_buf = getBuffer();
    }

    /**
     * Returns a buffer to the cache for reuse.
     *
     * Performance: O(1) operation with size limit check
     *

        this.cache = new Object[maxBuffers];
        this.bufferSize = maxSize;
    }

    /**
     * {@inheritDoc}
     *
     * @see jcifs.BufferCache#getBuffer()
     */
    @Override
    public byte[] getBuffer() {
        synchronized (this.cache) {
            byte[] buf;

            if (this.freeBuffers > 0) {
                for (int i = 0; i < this.cache.length; i++) {

        // When - Get a buffer
        byte[] buffer = BufferCache.getBuffer();

        // Then - Buffer should have expected size
        assertNotNull(buffer, "Buffer should not be null");
        assertEquals(SmbComTransaction.TRANSACTION_BUF_SIZE, buffer.length, "Buffer should have TRANSACTION_BUF_SIZE");

        // The validation in getBuffer() ensures size is within bounds (0 < size <= 1MB)

 */
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);

    }

    /**
     * Get the underlying buffer
     *
     * @return memory buffer
     * @throws IllegalStateException if memory region has been invalidated
     */
    public ByteBuffer getBuffer() {
        if (!valid) {
            throw new IllegalStateException("Memory region invalidated");
        }
        return buffer;
    }

    /**
     * Get local memory key
     *

        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);

        resp.reset();

        long k;

        /*
         * First request w/ interim response
         */
        try {
            req.setBuffer(getContext().getBufferCache().getBuffer());
            req.nextElement();
            if (req.hasMoreElements()) {
                final SmbComBlankResponse interim = new SmbComBlankResponse(getContext().getConfig());

  private final FbosByteSource byteSource;
  private final State state;

  /** ByteArrayOutputStream that exposes its internals. */
  private static final class MemoryOutput extends ByteArrayOutputStream {
    byte[] getBuffer() {
      return buf;
    }

    int getCount() {
      return count;
    }
  }

  /** Returns the file holding the data (possibly null). */
  @VisibleForTesting
  @Nullable File getFile() {