Websocket server can crash out of event loops if connection un-gracefully severed

[qdot]

Taken from intiface/intiface-cli-rs#5

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After a few times closing + restarting some scripts, I noticed the Rust server would stop accepting connections if the connection was not closed gracefully too many times.

Steps to reproduce:

1. Run Intiface's Rust server
2. Run a script that connects to the server (e.g. the Python example)
3. Terminate that script with Ctrl+C, or otherwise end it in a non-graceful way
4. IntifaceCLI will display an error such as:

thread '<unnamed>' panicked at 'called `Result::unwrap()` on an `Err` value: Protocol("Connection reset without closing handshake")', /home/runner/.cargo/registry/src/github.com-1ecc6299db9ec823/buttplug-0.7.2/src/connector/transport/websocket/websocket_server.rs:59:5

5. Continue doing this several more times.
6. After 5 or so attempts, the script will fail to connect to the server anymore.

Could not connect to server, exiting: [Errno 111] Connect call failed ('127.0.0.1', 12345)

The server appears to accept new connections if they are all closed gracefully, but not if they are non-graceful.

Expected behavior:

The server would continue to accept new connections.