if getCert == nil {
		return nil
	}

	tlsConfig := &tls.Config{
		PreferServerCipherSuites: true,
		MinVersion:               tls.VersionTLS12,
		NextProtos:               []string{"http/1.1", "h2"},
		GetCertificate:           getCert,
		ClientSessionCache:       tls.NewLRUClientSessionCache(tlsClientSessionCacheSize),
	}