we are using the String.replaceAll() method that creates Pattern internally every time:

    /**
     * Construct a String-based encoding based off the type. leadingData
     * is not used with this method.
     * @return PEM in a string
     */
    public static String pemEncoded(PEM pem) {
        String p = pem.content().replaceAll("(.{64})", "$1\r\n");
        return pemEncoded(pem.type(), p);
    }

We already have cached Patterns for other cases, we should do the same here.