Using Rust and winapi for the Get Started with Win32 and C++ tutorial. Drew from post and comments here: https://gist.github.com/TheSatoshiChiba/6dd94713669efd1636efe4ee026b67af and here: https://drywa.me/2017/07/02/simple-win32-window-with-rust/ and here: https://www.codeproject.com/Questions/279139/Mouse-leave-message-is-not-received-when-it-leaves