In this code adapted straight from the official mio example code:
use std::error::Error;
use std::io::Read;
use std::time::Duration;
use mio::net::{TcpListener};
use mio::{Events, Interest, Poll, Token};
const SERVER: Token = Token(0);
fn main() -> Result<(), Box<dyn Error>> {
let addr = "127.0.0.1:8080".parse()?;
let mut server = TcpListener::bind(addr)?;
let mut events = Events::with_capacity(128);
let mut poll = Poll::new()?;
poll.registry().register(&mut server, SERVER, Interest::READABLE)?;
loop {
match poll.poll(&mut events, Some(Duration::from_secs(10))) {
Ok(()) => {
if !events.is_empty() {
println!("event(s) have been received!");
for event in events.iter() {
match event.token() {
SERVER => {
println!("server event!");
let connection = server.accept();
println!("--> accepted!");
if let Ok((mut stream, _addr)) = connection {
let mut buffer = [0; 8192];
if let Ok(len) = stream.read(&mut buffer) {
println!("len = {}", len);
}
}
println!("--> dropped!");
}
_ => unreachable!(),
}
}
} else {
println!("timeout!");
}
},
Err(err) => println!("Poll error: {}", err),
}
}
}
Why do I only receive the event for the very first incoming connection, but then never any event is processed again, even though I try to connect to the server continuously? 
Note: The code is definitely not blocked, as the poll regularly exists with a timeout every 10 secs...
(If I terminate the process and re-start it, then again, I can receive one connection, but no more)
Thanks for any help!
Output:
C:\Source\mio_test>cargo run
Compiling mio_test v0.1.0 (C:\Source\mio_test)
Finished dev [unoptimized + debuginfo] target(s) in 1.42s
Running `target\debug\mio_test.exe`
timeout!
timeout!
event(s) have been received!
server event!
--> accepted!
--> dropped!
timeout!
timeout!
timeout!
timeout!
timeout!
...
Any subsequent attempt (except very first!) to connect to the server (via cURL) just hangs 
