docs: public boolean isLast() {
          Object isLast = getHeader(WebSocketMessageHeaders.WEB_SOCKET_IS_LAST);
  
          if (isLast != null) {
              if (isLast instanceof String) {
                  return Boolean.valueOf(isLast.toString());
              } else {
                  return (Boolean) isLast;
              }
          }
  
          return true;
      }