public <PRODUCER extends AnyConfigProducer> void register(PRODUCER producer) {
        UserConfigRepo userConfigs = producer.getUserConfigs();
        Map<Path, FileReference> registeredFiles = new HashMap<>();
        for (ConfigDefinitionKey key : userConfigs.configsProduced()) {
            ConfigPayloadBuilder builder = userConfigs.get(key);
            try {
                register(builder, registeredFiles, key);
            } catch (IllegalArgumentException e) {
                throw new IllegalArgumentException("Invalid config in services.xml for '" + key + "': " +
                                                   Exceptions.toMessageString(e));
            }
        }
    }
Registers user configured files for a producer for file distribution.
config-model/src/main/java/com/yahoo/vespa/model/filedistribution/UserConfiguredFiles.java