The newly released instrumentation module in LlamaIndex's latest version (v0.10.20) offers a structured and flexible approach to event and span management, replacing the legacy callbacks module. The new module introduces several core components, including Event, EventHandler, Span, SpanHandler, and Dispatcher, designed to optimize monitoring and management of LLM applications. These components work together to provide granular views of application operation, pinpoint notable events, and track sequences of operations within complex applications. By integrating with Arize Phoenix, developers can fine-tune performance, diagnose issues, and enhance the overall functionality of their LLM applications, achieving deeper insights and more effective management of their systems.