public SamlServiceProviderBuilder credentialResolver(CredentialResolver credentialResolver) {
        this.credentialResolver =
                new CredentialResolverAdapter(requireNonNull(credentialResolver, "credentialResolver"));
        return this;
    }
Sets a {@link CredentialResolver} for this service provider.
saml/src/main/java/com/linecorp/armeria/server/saml/SamlServiceProviderBuilder.java