message: Use explicit microsecond constructor for std::time::Duration
diff: @@ -313,7 +313,7 @@ impl<TypeState> ConnectionOptions<TypeState> {
  });
  conn.reader = Some(read_loop);
  - let usec = Duration::new(0, 1_000);
  + let usec = Duration::from_micros(1);
  let wait: [Duration; 5] = [10 * usec, 100 * usec, 500 * usec, 1000 * usec, 5000 * usec];
  let wbuf = conn.writer.clone();
  