@Override
    public ByteBuffer getKeyBuffer() {
        if (keyBuffer == null) {
            throw new RuntimeException(LogUtil.message("The keyBuffer has been returned to the pool"));
        }
        return keyBuffer;
    }
Wrapper for a pair of {@link ByteBuffer}s obtained from a {@link ByteBufferPool} that can be used
with a try with resources block as it implements {@link AutoCloseable}.
stroom-bytebuffer/src/main/java/stroom/bytebuffer/PooledByteBufferPairImpl.java