* x11: Windows are Sync again
Fixes#472
* Add test ensuring that Window is Sync
Window must be Sync for Vulkano's Arc<FramebufferAbstract> to be usable.
This commit only updates the top-level API to get some early feedback.
None of the platform-specific code has been updated yet. I'm hoping to
get around to this over the next couple days however if someone more
familiar with the windows backend would like to do a PR against this
fork that would be a great help.
Closes#187.
invariants
This also removes the need for "box"ing the callback in favour of
storing a raw `*mut` pointer. We can do this by ensuring that we never
store the pointer for longer than the lifetime of the user callback,
which is the duration of a call to `poll_events` or `run_forever`.
Also removes old commented out event code from the window module.