Panic when syncing many entities

[mvesterli]

If the synchronization message is greater than supported by the socket, it fails to send and therefore panics.
On windows 10 this limit is 64kB, which is ~2500 empty entities and significantly less when components are involved.

This code causes the error on my machine.

extern crate amethyst;
extern crate amethyst_editor_sync;

use amethyst::prelude::*;
use amethyst_editor_sync::*;

struct TestState;

impl<'a, 'b> SimpleState<'a, 'b> for TestState {
    fn on_start(&mut self, data: StateData<GameData>) {
        for _ in 0..2_500 {
            data.world.create_entity().build();
        }
    }
}

fn main() -> amethyst::Result<()> {
    let editor_sync_bundle = SyncEditorBundle::new();
    let game_data = GameDataBuilder::default()
        .with_bundle(editor_sync_bundle)?;
    let mut game = Application::build(".", TestState)?
        .build(game_data)?;
    game.run();
    Ok(())
}

[randomPoison]

Ah, thanks for finding this! I'm pretty sure I've run into this issue and hadn't yet figured out where the crash was coming from. We could fix this with UDP pretty easily by splitting the message across multiple packets, though this also makes me want to investigate using proper IPC communication or maybe even TCP.

Ideally ipc-channel would be the way to go, but Windows support is still a work in progress. So in the meantime I'd probably suggest we go with TCP, since I think that will be the easiest for editor implementations to support.

[randomPoison]

This would also be a good thing to add a regression test for!

[randomPoison]

Thinking about it a bit more, it's not going to be so trivial to convert to TCP 🤔 With TCP we'd have to manually manage connection states, send heartbeats, and track disconnections after a timeout. This is stuff we'll want to do eventually, but I'm not sure it's worth putting in that kind of effort for now. Instead I'm going to doing a pretty simple implementation of splitting the state message across multiple UDP packets.