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// { "preopens": { "/scratch": "scratch" } }
use std::io::Write;
fn main() {  let mut file = std::fs::File::create("/scratch/file").unwrap();
  assert!(file.write(b"Hello").is_ok());  assert!(file.sync_data().is_ok());  assert_eq!(std::fs::read("/scratch/file").unwrap(), b"Hello");
  assert!(file.write(b", world!").is_ok());  assert!(file.sync_data().is_ok());  assert_eq!(std::fs::read("/scratch/file").unwrap(), b"Hello, world!");}