message: Explicitly match on all ControlOp variants to be more future-proof
diff: @@ -1058,7 +1058,16 @@ impl Connection<Connected> {
  match parser::parse_control_op(reader)? {
  parser::ControlOp::Pong => Ok(()),
  parser::ControlOp::Err(e) => Err(Error::new(ErrorKind::ConnectionRefused, e)),
  - _ => Err(Error::new(ErrorKind::ConnectionRefused, "Protocol Error")),
  + other @ parser::ControlOp::Ping
  + | other @ parser::ControlOp::Msg(_)
  + | other @ parser::ControlOp::Info(_)
  + | other @ parser::ControlOp::Unknown(_) => {
  + eprintln!(
  + "encountered unexpected control op during connection: {:?}",
  + other
  + );
  + Err(Error::new(ErrorKind::ConnectionRefused, "Protocol Error"))
  + }
  }
  }
  }
  