Squeezing every millisecond: How we rebuilt the Datadog Lambda Extension in Rust | Datadog

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The Datadog Lambda Extension was re-engineered from Go to Rust, achieving significant performance improvements: 82% reduction in cold start latency, 40% reduction in memory usage, and a binary size decrease from 55 MB to 7 MB. This involved adopting Rust for its memory safety and small binary output, and implementing specific design constraints for the Lambda environment, such as minimizing impact on the Lambda function handler and post-runtime duration. Manual implementation of AWS API calls was used to avoid SDK overhead. Flexible flush strategies (end, race, periodic) were introduced to optimize telemetry delivery based on workload type.