message: flush stdout/stderr to make sure it appears on the screen
diff: @@ -390,10 +390,15 @@ pub trait EvalContextExt<'a, 'mir, 'tcx: 'a+'mir>: crate::MiriEvalContextExt<'a,
  use std::io::{self, Write};
  let buf_cont = this.memory().read_bytes(buf, Size::from_bytes(n))?;
  + // We need to flush to make sure this actually appears on the screen
  let res = if fd == 1 {
  - io::stdout().write(buf_cont)
  + let res = io::stdout().write(buf_cont);
  + io::stdout().flush().unwrap();
  + res
  } else {
  - io::stderr().write(buf_cont)
  + let res = io::stderr().write(buf_cont);
  + io::stderr().flush().unwrap();
  + res
  };
  match res {
  Ok(n) => n as i64,
  