static WebSocketManager webSocketManager;

sclass WebSocketManager {
  Set webSockets = synchroHashSet();

  *() {
    replaceCollection(webSockets, subBot_getMyWebSockets());
    ifdef WebSocketManager_debug
      print("Have " + n2(webSockets, "web socket") + ".");
    endifdef
  }

  void onNewWebSocket(O ws, S uri) {
    ifdef WebSocketManager_debug
      print("New web socket!");
    endifdef
    webSockets.add(ws);
  }
  
  void onWebSocketMessage(O ws, S msg) {
    ifdef WebSocketManager_debug
      print("Got message: " + msg);
    endifdef
  }

  void onWebSocketClosed(O ws) {
    ifdef WebSocketManager_debug
      print("Closed web socket");
    endifdef
    webSockets.remove(ws);
  }
 
  void sendToAllWebSockets(S msg) {
    for (O ws : webSockets)
      pcall(ws, 'send, msg);
  }
  
  Collection webSockets() {
    ret cloneList(webSockets);
  }
  
  bool isEmpty() { ret empty(webSockets); }
  
  void close(O ws) { call(ws, 'close); }
}

static void onNewWebSocket(O ws, S uri) {
  if (webSocketManager != null)
    webSocketManager.onNewWebSocket(ws, uri);
}

static void onWebSocketMessage(O ws, S msg) {
  if (webSocketManager != null)
    webSocketManager.onWebSocketMessage(ws, msg);
}

static void onWebSocketClosed(O ws) {
  if (webSocketManager != null)
    webSocketManager.onWebSocketClosed(ws);
}

Began life as a copy of #1014671