This showcases a Unity Native Plugin written in Rust that clears the screen using Direct3D 11 (and logs a bunch of messages when loading for the first time).
unity3d-sys contains raw, unsafe bindings to the native Unity API.
src/lib.rs uses those to talk to Unity and clear the screen with a red color.
RustNativePlugin-Unity contains a sample Unity project that uses the plugin.
The plugin DLL can be built with cargo b from this directory.
To test the Unity project, copy the plugin DLL (and its PDB if you wish to debug) into the Assets/Plugins/ folder of the Unity project.
Functionality has been tested with Unity 2019.4.1f1 (LTS).