getInitParameter(AUTH_SCHEME_PROVIDERS_PROPERTY, authSchemeProviderMap, Map.class);
        if (factoryMap != null) {
            for (final Map.Entry<String, AuthSchemeProvider> entry : factoryMap.entrySet()) {
                authSchemeProviderBuilder.register(entry.getKey(), entry.getValue());
            }
        }

        // user agent
        userAgent = getInitParameter(USER_AGENT_PROPERTY, userAgent, String.class);