code: @Override
      public boolean stop() {
          synchronized(MetricCollectorSupport.class) {
              if (uploaderThread != null) {
                  uploaderThread.cancel();
                  uploaderThread.interrupt();
                  uploaderThread = null;
                  if (singleton == this) { // defensive check
                      singleton = null;
                  }
                  return true;
              }
          }
          return false;
      }
docs: Stops this collector immediately, dropping all pending metrics in memory.