use plugin::prelude::*; #[export]pub fn noop() {} #[export]pub fn constant() -> u32 {    27} #[export]pub fn identity(i: u32) -> u32 {    i} #[export]pub fn add(a: u32, b: u32) -> u32 {    a + b} #[export]pub fn swap(a: u32, b: u32) -> (u32, u32) {    (b, a)} #[export]pub fn sort(mut list: Vec<u32>) -> Vec<u32> {    list.sort();    list} #[export]pub fn print(string: String) {    println!("to stdout: {}", string);    eprintln!("to stderr: {}", string);} #[import]fn mystery_number(input: u32) -> u32; #[export]pub fn and_back(secret: u32) -> u32 {    mystery_number(secret)} #[import]fn import_noop() -> (); #[import]fn import_identity(i: u32) -> u32; #[import]fn import_swap(a: u32, b: u32) -> (u32, u32); #[export]pub fn imports(x: u32) -> u32 {    let a = import_identity(7);    import_noop();    let (b, c) = import_swap(a, x);    assert_eq!(a, c);    assert_eq!(x, b);    a + b // should be 7 + x} #[import]fn import_half(a: u32) -> u32; #[export]pub fn half_async(a: u32) -> u32 {    import_half(a)} #[import]fn command_async(command: String) -> Option<Vec<u8>>; #[export]pub fn echo_async(message: String) -> String {    let command = format!("echo {}", message);    let result = command_async(command);    let result = result.expect("Could not run command");    String::from_utf8_lossy(&result).to_string()}