Unit 20 · Language valence: C# under policy · q27b

**Gut Reaction:** It’s a trap. You’re trying to boil the ocean with a single language constraint. C# is powerful, but forcing it to handle high-performance 3D rendering, low-latency async orchestration, and native plugin boundaries on mobile *and* desktop simultaneously is a recipe for a bloated, slow, and unmaintainable monolith. The "100% C#" policy ignores the reality that mobile OSes and GPU drivers speak C/C++/Rust, not IL. **Top 3 Technical Risks:** 1. **Mobile Performance & Memory Overhead:** C# on mobile (via Xamarin/MAUI or Unity) runs on a managed runtime. A 3D viewport with complex async data streams will cause GC pauses, frame drops, and excessive memory usage. Mobile devices have strict thermal and battery constraints; the overhead of the CLR + JIT/AOT compilation + marshaling between managed and native UI/GPU layers will likely make the app feel sluggish or crash under load. 2. **Plugin (greedy generation)

**What Breaks First:** The **3D Viewport on Android**. Specifically, the **Garbage Collection (GC) pauses** and **JIT/AOT compilation overhead** will kill your 120 FPS target. Mid-range Android devices have limited RAM and CPU headroom. C#’s managed memory model creates unpredictable latency spikes when the GC kicks in during heavy async data ingestion or 3D scene updates. Even with AOT (Ahead-of-Time) compilation, the lack of direct memory control and the overhead of the runtime will prevent consistent 120 FPS in a complex 3D scene. **What You Do About It (The C#-Only Compromise):** 1. **Aggressive GC Control & Object Pooling:** * **Zero-Allocation Hot Path:** Refactor the 3D rendering loop and async data processing to be **zero-allocation**. Use `struct`-based data, `Span<T>`, and `Memory<T>` to avoid heap allocations. * **Object Pools:** (greedy generation)