code: private void timeoutExpired(final Timeout timeout, final TimeoutContext context) {
          try {
              removeExpiredTimeout(timeout);
  
              for (TimeoutExpired callback : callbacks) {
                  if (callback instanceof TimeoutExpirationCallback) {
                      ((TimeoutExpirationCallback) callback).expired(timeout, context);
                  } else {
                      callback.expired(timeout);
                  }
              }
          } catch (Exception ex) {
              // catch all exceptions. otherwise calling timeout thread of timers thread pool will be terminated.
              LOG.error("Error handling timeout.", ex);
          }
      }
docs: Called by timeout task once timeout has expired.