Fixes#1892
The following code is a cut down version of the issue, and crashes the same way:
```rust
enum AssetLifecycleEvent <T> {
Create(T),
Free
}
fn main() {
let (sender, _receiver) = crossbeam_channel::unbounded();
sender.send(AssetLifecycleEvent::<[u32; 32000]>::Free).unwrap();
}
```
- We're creating a channel that need to be able to hold `AssetLifecycleEvent::Create(T)` which has the size of our type `T`
- The two variants of the enums have a very different size
By keeping `T` boxed while sending through the channel, it doesn't crash
0a8576b710