private String readLengthPrefixedAnsiString(InputStream is) throws IOException, TikaException {
        long len = readUInt(is);
        byte[] bytes = readBytes(is, len);
        try {
            return new String(bytes, WIN_ASCII);
        } catch (UnsupportedEncodingException e) {
            //shouldn't ever happen
            throw new IOException("Unsupported encoding");
        }
    }
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