private byte[] readBytes(InputStream is, long len) throws IOException, TikaException {
        //initByteArray tests for "reading of too many bytes"
        byte[] bytes = initByteArray(len);
        IOUtils.readFully(is, bytes);
        return bytes;
    }
can return null if there is a linked object
instead of an embedded file
tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-microsoft-module/src/main/java/org/apache/tika/parser/microsoft/rtf/RTFObjDataParser.java