SendInput with Rust WinAPI crate (not for actual use in a serious rust program, just an example)

Cargo.toml

[package]
name = "sendinputexample"
version = "0.1.0"
authors = ["Dayaa <dayisus.1337@gmail.com>"]
edition = "2018"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
winapi = { version = "0.3.7", features = ["winuser"] }

main.rs

#[cfg(windows)] extern crate winapi;
use std::io::Error;

#[cfg(windows)]
fn press_key(key: u16, flags: u32) -> Result<(), Error> {
    use winapi::um::winuser::{INPUT_u, INPUT, INPUT_KEYBOARD, KEYBDINPUT, SendInput};
    
    let mut input_u: INPUT_u = unsafe { std::mem::zeroed() };
    unsafe {
        *input_u.ki_mut() = KEYBDINPUT {
            wVk: key,
            dwExtraInfo: 0,
            wScan: 0,
            time: 0,
            dwFlags: flags
        }
    }

    let mut input = INPUT {
        type_: INPUT_KEYBOARD,
        u: input_u
    };
    let ipsize = std::mem::size_of::<INPUT>() as i32;
    unsafe {
        SendInput(1, &mut input, ipsize);
    };
    Ok(())
    
    
}
#[cfg(not(windows))]
fn press_key(key: u16) -> Result<(), Error> {
    Ok(())
}
fn main() {
    const KEYUP: u32 = 0x0002;
    press_key(0x91, 0);
    println!("dw");
    std::thread::sleep(std::time::Duration::from_millis(30));
    println!("up");
    press_key(0x91, KEYUP);
}