When a Rust program feels sluggish, adding instrumentation can shine a light on where the time is going. In this post, we’ll walk through a guided journey of using Tokio’s tracing framework and the tracing-texray tool to drill into performance issues. We assume you’re familiar with the basics of tokio-tracing (if not, see the Tokio tracing introduction for spans and events fundamentals). Our journey will start with a simple sequential task, then ramp up to parallel execution and illustr...