private void makeSimpleEscape(char source, char dest) {
            needEscape[source] = 1;
            replacement1[source] = '\\';
            replacement2[source] = (byte) dest;
        }
Returns a String where each byte b in `bytes` is replaced by "%02x".formatted(b).
vespajlib/src/main/java/com/yahoo/text/StringUtilities.java