`:telemetry` is a lightweight, dynamic dispatching library in Elixir that enables developers to instrument their applications. It helps in collecting metrics, monitoring performance, and gaining insights into system behavior.

:telemetry is an essential component of the Elixir ecosystem that provides a framework for instrumentation, allowing developers to collect metrics and monitor the performance of their applications. By instrumenting your code with telemetry events, you can gain valuable insights into how your application behaves under various conditions, which is crucial for identifying bottlenecks and improving performance. Telemetry operates on a publish-subscribe model, where events can be emitted from your application and collected by listeners that respond to those events. This allows for flexible and decoupled monitoring solutions. You can use telemetry to track a wide range of metrics, such as request times, error rates, or database query performance. To emit events, you use the :telemetry.execute/3 function, providing a name for the event, a measurement map, and additional metadata. On the listener side, you can define handlers that will be triggered when specific events occur, enabling you to log, aggregate, or visualize the metrics. By integrating telemetry into your Elixir applications, you can proactively monitor system health and performance, making it easier to respond to issues before they impact your users.