@Override
    public void serialize(FileBackedOutputStream fbos, JsonGenerator gen, SerializerProvider provider) throws IOException {
        gen.writeBinary(fbos.asByteSource().openStream(), Math.toIntExact(fbos.asByteSource().size()));
    }
@author Marc Savy {@literal <marc@blackparrotlabs.io>}
manager/api/export-import/src/main/java/io/apiman/manager/api/exportimport/json/FbosSerializer.java