During September 2025, Tarassov enhanced the microsoft/documentdb repository by developing a configurable parallelism feature for the gateway’s Tokio runtime. He introduced a new async_runtime_worker_threads parameter, allowing operators to fine-tune runtime worker threads and optimize gateway throughput and resource utilization in production environments. This work involved updating both DocumentDBSetupConfiguration and SetupConfiguration to expose the new parameter, and implementing a multi-threaded Tokio runtime initialization in the main application. Leveraging Rust, asynchronous programming, and configuration management skills, Tarassov delivered a focused, well-integrated feature that addressed performance tuning needs with a clear, maintainable approach, demonstrating depth in system design and implementation.