static boolean isTLSv13Cipher(String cipher) {
        // See https://tools.ietf.org/html/rfc8446#appendix-B.4
        return TLSV13_CIPHERS.contains(cipher);
    }
@Test
    public void testIsTLSv13Cipher() {
        assertTrue(SslUtils.isTLSv13Cipher("TLS_AES_128_GCM_SHA256"));
        assertTrue(SslUtils.isTLSv13Cipher("TLS_AES_256_GCM_SHA384"));
        assertTrue(SslUtils.isTLSv13Cipher("TLS_CHACHA20_POLY1305_SHA256"));
        assertTrue(SslUtils.isTLSv13Cipher("TLS_AES_128_CCM_SHA256"));
        assertTrue(SslUtils.isTLSv13Cipher("TLS_AES_128_CCM_8_SHA256"));
        assertFalse(SslUtils.isTLSv13Cipher("TLS_DHE_RSA_WITH_AES_128_GCM_SHA256"));
    }