return buf.length - start;
    }

    /**
     * Returns the available space at the tail of the buffer.
     *
     * @return the available tail space
     */
    public int getTailSpace() {
        return buf.length - index;
    }

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

        return this.buf.length - this.start;
    }

    /**
     * Returns the available space at the tail of the buffer.
     *
     * @return the available tail space
     */
    public int getTailSpace() {
        return this.buf.length - this.index;
    }

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

        assertEquals(buffer.length - 100, offsetBuffer.getCapacity());
    }

    @Test
    void testGetTailSpace() {
        ndrBuffer.setIndex(100);
        assertEquals(buffer.length - 100, ndrBuffer.getTailSpace());
    }

    @Test
    void testGetBuffer() {
        assertSame(buffer, ndrBuffer.getBuffer());
    }

    @Test
    void testAlignWithValue() {
        // Align to 4-byte boundary with a fill value