code: public SSLEngine newEngine() {
          if (nextProtocols.isEmpty()) {
              return new OpenSslEngine(ctx, bufferPool, null);
          } else {
              return new OpenSslEngine(
                      ctx, bufferPool, nextProtocols.get(nextProtocols.size() - 1));
          }
      }
docs: Returns a new server-side {@link SSLEngine} with the current configuration.