public static DecodedChar unknownChar(final byte[] malFormedBytes) {
            Objects.requireNonNull(malFormedBytes);
            return new DecodedChar(
                    UNKNOWN_CHAR_REPLACEMENT_STRING,
                    malFormedBytes.length,
                    true,
                    malFormedBytes);
        }
Char to use represent 1 or more bytes that can't be decoded
stroom-pipeline/src/main/java/stroom/pipeline/reader/ByteStreamDecoder.java