Implement Index<usize> for Events

[dtolnay]

The mio::Events type looks a lot like Vec - it has a function get(usize) -> Option<Event> which returns None if the index is out of bounds, and it has IntoIterator. It would be convenient to implement Index to enable square-bracket indexing that panics on out of bounds.

println!("{:?}", events[0]);

[ahmedcharles]

This isn't trivial. The epoll implementation of Events doesn't store Event instances directly, it stores libc::epoll-event instances. This is why get(usize) returns Option<Event> rather than Option<&Event>. Index requires &Event, which can't be a temporary, because it doesn't live long enough.

[alexcrichton]

Ah yes this isn't implementable easily and intentionally so, we often perform translations on the returned events from the system to coalesce and/or generate more mio events.

[carllerche]

Actually I'm pretty sure we wanted to deprecate indexed access in favor of an iterator only API.

[dtolnay]

I filed #697 to follow up if necessary.