docs: public boolean sendMessage(WebSocketMessage<?> message) {
          boolean sentSuccessfully = false;
          if (sessions.isEmpty()) {
              LOG.warn("No Web Socket session exists - message cannot be sent");
          }
  
          for (WebSocketSession session : sessions.values()) {
              if (session != null && session.isOpen()) {
                  try {
                      session.sendMessage(message);
                      sentSuccessfully = true;
                  } catch (IOException e) {
                      LOG.error(String.format("(%s) error sending message", session.getId()), e);
                  }
              }
          }
          return sentSuccessfully;
      }