@Override
    public String toString() {
        return "HexDump{" +
                "lines=" + lines +
                ", charset=" + charset +
                '}';
    }
@return The size of the hex dump when output as a string. Not the
number of chars rendered by the hex dump.
stroom-util-shared/src/main/java/stroom/util/shared/string/HexDump.java