Remove odd patching matching
Replace std::sync::Mutex with spin::Mutex in GpuFuture
Reduce GpuFuture usage to one explicit allocation instead of two
Fix examples to poll the device in the background when using map_read or map_write
Remove device.poll from GpuFuture::poll and document future invariants
Massively simplify examples
Use Arc::clone(...) instead of arc.clone()
Switch println to log::info