Generic handle wrapper pattern (IHandle<THandle>) that encapsulates native handles (HWND, HDC, HICON, etc.) and uses GC.KeepAlive to prevent premature garbage collection of the owning object. This pattern is used extensively in P/Invoke extension methods to safely pass handles to native APIs. It is self-contained, demonstrates deep understanding of .NET interop and GC behavior, and can be extracted for any project that needs safe native handle management.

A discriminated union struct using explicit layout (FieldOffset) to efficiently store various types (int, float, DateTimeOffset, Color, etc.) in a single 8-byte value. It uses type flags to distinguish the stored type and provides packed representations for common types (e.g., PackedColorFlag). This is a high-performance alternative to boxing or object wrappers, and is reusable in any .NET project requiring compact, type-safe storage of heterogeneous values.

A ref struct that implements RAII for GDI device context state management. It saves and restores the state of a GDI DC (via SaveDC/RestoreDC) in a using block, ensuring proper cleanup even on exceptions. This is part of a family of similar scopes (SelectObjectScope, SetTextColorScope, SetBkModeScope, etc.) that provide safe, composable wrappers for GDI operations. The pattern is self-contained, demonstrates advanced use of ref structs and IDisposable, and can be extracted for any project that interacts with GDI.