private byte[] concatLengthPrefixed(HttpProtocol ... protocols) {
        ByteArrayOutputStream os = new ByteArrayOutputStream();
        for (HttpProtocol protocol : protocols) {
            String protocolStr = protocol.toString().toLowerCase();
            os.write(protocolStr.length());
            os.write(protocolStr.getBytes(Charset.forName("UTF-8")), 0, protocolStr.length());
        }
        return os.toByteArray();
    }
Http SSL codec enables Application-Layer Protocol Negotiation(ALPN).

See http://tools.ietf.org/html/draft-agl-tls-nextprotoneg-04#page-4

@author Megatron King
@since 2019/1/3 23:31
netbare-core/src/main/java/com/github/megatronking/netbare/http/HttpSSLResponseCodec.java