Over a two-month period, contributed performance-focused enhancements to open-telemetry-dotnet and elastic/apm-agent-dotnet, targeting backend efficiency and robustness. In open-telemetry-dotnet, optimized OTLP exporter header parsing by refactoring logic to use ReadOnlySpan<char> in C#, reducing allocations and improving throughput under high load, with comprehensive unit tests ensuring correctness across edge cases. For elastic/apm-agent-dotnet, improved PayloadSenderV2 by reusing a single MemoryStream, addressing memory fragmentation and reducing garbage collection pressure in long-running deployments. Work emphasized memory management, performance optimization, and test-driven development, with changes validated through benchmarks and safety tests to ensure stability and maintainability in production environments.