Handlers

Every time you run the event loop, you can supply it with a Handler to call when an event occurs that the consumer registered interest in.

The Handler has a method for every kind of event that mio supports:

pub trait Handler<T: Token, M: Send> {
    /// A registered IoHandle has available data to read
    fn readable(&mut self, reactor: &mut EventLoop<T, M>, hint: ReadHint, token: T);

    /// A registered IoHandle is available to write to
    fn writable(&mut self, reactor: &mut EventLoop<T, M>, token: T);

    /// A registered timer has expired
    fn timer(&mut self, reactor: &mut EventLoop<T, M>, token: T);

    /// A message has been delivered
    fn notify(&mut self, reactor: &mut EventLoop<T, M>, msg: M);

    /// A signal has been delivered to the process
    fn signal(&mut self, reactor: &mut EventLoop<T, M>, info: mio::SigInfo);
}

When registering interest in an IoHandle or when registering a timer, the consumer provides a Token (which wraps a copyable pointer-sized value). This same token is provided to the Handle.