private void createListeners() {
        factoryManager.getEventAnalyzerListenerFactories()
                      .forEach(factory -> listeners.add(factory.create(moduleManager)));
    }
Analyze the collected event data, is the entry point for event analysis.
oap-server/analyzer/event-analyzer/src/main/java/org/apache/skywalking/oap/server/analyzer/event/EventAnalyzer.java