private static @Nullable X509TrustManager findX509TrustManager(TrustManager[] managers) {
    for (TrustManager manager : managers) {
      if (manager instanceof X509TrustManager) {
        return (X509TrustManager)manager;
      }
    }
    return null;
  }
private static @Nullable X509TrustManager findX509TrustManager(TrustManager[] managers)