Content by Stephen Toub (2)

Stephen Toub breaks down how GitHub rewrote the Copilot agent runtime from a TypeScript/Node.js/V8 stack into a production Rust runtime, largely using Copilot agents. He explains the architectural drivers (in-process hosting, lower memory, better startup), the incremental port strategy, interop layers, regression patterns, and the measured performance gains.

Stephen Toub walks through a large set of runtime and library performance changes in .NET 11, with runnable micro-benchmarks and disassembly examples. It covers JIT optimizations (devirtualization, escape analysis, bounds-check removal), a new runtime-driven async implementation, SIMD/codegen improvements, and faster paths across core libraries like networking, JSON, regex, and collections.