You run a single command to instantiate a family of cross-platform Cargo projects, one your platform-agnostic backend, and one for each of your target platforms: Linux, Windows, Mac, Android, iOS, of course, but also the entire impending IoT down to the smallest real-time device. Your platform-specific projects come with safe Rust bindings to the system platform (ala Xamarin).
Another single command builds and tests this from a single host system on an armada of virtual machines, emulators and cloud systems. Your tests run on a wide variety of standardized machine images, including those used for upstream Rust's own integration testing.
Another single command packages this for various Linuxes and app stores, deploys to your devices and cloud services.