RustConf 2019 - Tokio-Trace: Scoped, Structured, Async-Aware Diagnostics by Eliza Weisman tokio-trace is a new set of Rust libraries that provide primitives for recording scoped, structured, and async-aware diagnostics. Unlike traditional logging, tokio-trace emits structured diagnostics that model the contextual and causal relationships between between events. tokio-trace was designed by the tokio project to solve problems with logging in asynchronous applications, but may be used in any Rust codebase. This talk presents the motivation and influences behind tokio-trace, introduces its core concepts, and demonstrates how it can be used.