void checkSupportedCipherSuites() {
        if (getSupportedCipherSuites() == null) {
            setSupportedCipherSuites(Collections.singletonList(HTTP2_DEFAULT_CIPHER));
        } else if (!getSupportedCipherSuites().contains(HTTP2_DEFAULT_CIPHER)) {
            throw new IllegalArgumentException("HTTP/2 server configuration must include cipher: " + HTTP2_DEFAULT_CIPHER);
        }
    }
@Test
    void testSetDefaultHttp2Cipher() {
        http2ConnectorFactory.checkSupportedCipherSuites();

        assertThat(http2ConnectorFactory.getSupportedCipherSuites()).containsExactly(
            "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256");
    }