//! Export traces over OTLP to a collector such as Jaeger or Datadog.
//!
//! Run a local collector, for example Jaeger all-in-one:
//!
//! ```sh
//! docker run --rm -p 4317:4317 -p 16686:16686 jaegertracing/all-in-one
//! ```
//!
//! Then `cargo run --example telemetry --features otel` and open the Jaeger UI
//! at http://localhost:16686. Requests carrying a W3C `traceparent` header
//! continue the upstream trace.
use *;
async
async