@Override
    public List<Byte> serializeToByteList() throws IOException {
        this.length.setDecodedValue(this.content.size());

        List<Byte> result = new ArrayList<>();
        result.addAll(this.length.serializeToByteList());
        result.addAll(this.content);

        return result;
    }
This method is used to convert the element of BinaryItem basic object into a byte List.

@return Return the byte list which store the byte information of BinaryItem.
tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-microsoft-module/src/main/java/org/apache/tika/parser/microsoft/onenote/fsshttpb/streamobj/basic/BinaryItem.java