Unicode output does not roundtrip

When I put the unicode character "∀" into cat, the output doesn't roundtrip:

Input:
∀
226 136 128 
Output:
€ˆ
195 162 194 136 194 128 

Code:

use rexpect::spawn;
use rexpect::error::*;

fn display(s: &str)
{
	println!("{}", s);
	for b in s.as_bytes()
	{
		print!("{} ", b);
	}
	println!("");
}
fn repl() -> Result<(), Error>
{
	let mut p = spawn("cat", Some(1000))?;

	let ex: String = "∀".to_string();
	p.send_line(&ex)?;
	let line = p.read_line()?;

	println!("Input:");
	display(&ex);
	println!("Output:");
	display(&line);
	Ok(())
}
fn main()
{
	repl().unwrap_or_else(|e| panic!("ftp job failed with {}", e));
}

Run the Rust reproduction shown with cat and trace the spawn, send_line, and read_line entry points. Verify where the Unicode bytes change during the round trip; done means sending ∀ through cat returns the same character and UTF-8 bytes.