private void doWriteIncrement() throws IOException {
        // write existing PDF
        IOUtils.copy(new RandomAccessInputStream(incrementalInput), incrementalOutput);
        // write the actual incremental update
        incrementalOutput.write(getBytes(output));
    }
Write an incremental update for a non signature case. This can be used for e.g. augmenting
signatures.

@throws IOException
tika-fuzzing/src/main/java/org/apache/tika/fuzzing/pdf/EvilCOSWriter.java