Rust Observability with OpenTelemetry

Datadog is evolving its observability stack for Rust services by contributing to OpenTelemetry and building dd-trace-rs, an opinionated Rust tracer. This aims to provide consistent tracing, context propagation, and sampling across services, improving incident investigation and reducing resource consumption. Key efforts include improving interoperability between the `tracing` crate and OpenTelemetry, and extending the OpenTelemetry pipeline with opinionated configurations for Datadog users. The new dd-trace-rs library builds on the OpenTelemetry Rust SDK, offering opinionated configurations for Datadog users, including automatic configuration via environment variables, consistent sampling strategies, and reliable context propagation. Significant upstream contributions to OpenTelemetry Rust and `tracing-opentelemetry` have improved interoperability between the `tracing` and OpenTelemetry APIs, fixing issues with context synchronization and span stacking, benefiting the broader Rust ecosystem.