throw new InvalidUserDataException("manifestContentCharset must not be null");
        }
        if (!Charset.isSupported(manifestContentCharset)) {
            throw new InvalidUserDataException(String.format("Charset for manifestContentCharset '%s' is not supported by your JVM", manifestContentCharset));
        }
        this.manifestContentCharset = manifestContentCharset;
    }

    /**

        writeCharset    | readCharset     | cause
        "'UNSUPPORTED'" | "'UTF-8'"       | "Charset for manifestContentCharset 'UNSUPPORTED' is not supported by your JVM"
        "'UTF-8'"       | "'UNSUPPORTED'" | "Charset for contentCharset 'UNSUPPORTED' is not supported by your JVM"
        null            | "'UTF-8'"       | "manifestContentCharset must not be null"
        "'UTF-8'"       | null            | "contentCharset must not be null"
    }