private String determineKey(String pathSoFar, String key) {
        return pathSoFar.length() == 0 ? key : pathSoFar + "." + key;
    }
@see io.apiman.gateway.engine.IEngineConfig#getGatewayInitializers(io.apiman.gateway.engine.IPluginRegistry)
gateway/platforms/vertx3/vertx3/src/main/java/io/apiman/gateway/platforms/vertx3/common/config/VertxEngineConfig.java