private static String normalize(String hostname) {
        if ("*".equals(hostname)) {
            return "*";
        } else {
            return TlsProviderUtil.normalizeHostname(hostname);
        }
    }
Sets the default {@link X509Certificate}s to the trusted certificates that is used for verifying
the remote endpoint's certificate if no specific trusted certificates are set for a hostname.

<p>The system default will be used if no specific trusted certificates are set for a hostname and no
default trusted certificates are set.
core/src/main/java/com/linecorp/armeria/common/TlsProviderBuilder.java