Function to_websocket 

pub fn to_websocket<T, F>(
    graph: &Graph,
    source: &Node<T>,
    request: WebSocketRequest,
    send_of: F,
) -> OutboundBundle<T, WebSocketSendResult>
where
    T: Clone + 'static,
    F: Fn(&T) -> WebSocketSend + 'static,

Creates or computes to_websocket.