code: public WebSocketContext sendJsonToPeers(Object data, boolean excludeSelf) {
          return sendToPeers(JSON.toJSONString(data), excludeSelf);
      }
docs: Send JSON representation of a data object to all connections connected to
  the same URL of this context with the connection of this context excluded
  
  @param data the data to be sent
  @param excludeSelf whether it should send to the connection of this context
  @return this context