Memory allocation error when using Events::new(EventSettings::new())

When using an event loop created with Events::new(EventSettings::new()) , more and more meory is used up until the process aborts with an out of memory error. The problem can be avoided by switching to use window.next() instead.

Here's a reduced test case:

extern crate graphics;
extern crate opengl_graphics;
extern crate piston;
extern crate piston_window;

use opengl_graphics::OpenGL;
use piston::event_loop::*;
use piston::input::*;
use piston_window::{PistonWindow, WindowSettings};

const BLACK: [f32; 4] = [0.0, 0.0, 0.0, 1.0];
const WHITE: [f32; 4] = [1.0, 1.0, 1.0, 1.0];

fn main() {
    let opengl = OpenGL::V3_2;

    let mut window: PistonWindow = WindowSettings::new("maze", [800, 600])
        .opengl(opengl)
        .exit_on_esc(true)
        .build()
        .unwrap();

    let mut events = Events::new(EventSettings::new());

    while let Some(event) = events.next(&mut window) {
        if let Some(_args) = event.render_args() {
            window.draw_2d(&event, |c, gl| {
                graphics::clear(BLACK, gl);

                for _row in 0..72 {
                    for _col in 0..120 {
                        let color = WHITE;
                        let box_rect =
                            graphics::rectangle::rectangle_by_corners(0.0, 0.0, 10.0, 10.0);
                        graphics::rectangle(color, box_rect, c.transform, gl);
                    }
                }
            });
        }
    }
}

The program aborts in about 2 minutes after attempting to allocate 8GB. If events is removed and window.next() is used in the while loop instead, the problem goes away.

Start by running the reduced example and compare Events::next(&mut window) with window.next(), confirming the unbounded memory growth. Trace the event-loop entry points used by Events::new(EventSettings::new()) and identify where allocations accumulate. Done means the Events path no longer exhausts memory and the reduced case remains functional.