# Advanced Features
This section covers advanced features of `rsActor` that enable more sophisticated actor system designs:
- [**Handler Traits**](advanced/handler_traits.md) — Type-erased message sending for heterogeneous actor collections
- [**Actor Control**](advanced/actor_control.md) — Type-erased lifecycle management
- [**Weak References**](advanced/weak_references.md) — Preventing memory leaks in actor graphs
- [**Metrics**](advanced/metrics.md) — Per-actor performance monitoring
- [**Dead Letter Tracking**](advanced/dead_letters.md) — Observability for failed message delivery
- [**Tracing & Observability**](advanced/tracing.md) — Structured logging and instrumentation spans
- [**Deadlock Detection**](advanced/deadlock_detection.md) — Runtime detection of circular `ask` dependencies