// (see grpc/xds/internal/client/xds.go securityConfigFromCluster).
func buildCommonTLSContext(sans []string) *tls.CommonTlsContext {
	var sanMatch []*matcher.StringMatcher
	if len(sans) > 0 {
		sanMatch = util.StringToExactMatch(sans)
	}
	return &tls.CommonTlsContext{
		TlsCertificateCertificateProviderInstance: &tls.CommonTlsContext_CertificateProviderInstance{

  protected void setUp() throws Exception {
    super.setUp();
    executor = new FakeExecutor();
    bus = new AsyncEventBus(executor);
  }

  public void testBasicDistribution() {
    StringCatcher catcher = new StringCatcher();
    bus.register(catcher);

    // We post the event, but our Executor will not deliver it until instructed.
    bus.post(EVENT);

    List<String> events = catcher.getEvents();