code: private void initSupportExecutor() {
          if (supportExecutor == null || supportExecutor.isShutdown()) {
              supportExecutor = Executors.newSingleThreadExecutor(new ThreadFactory() {
                  @Override
                  public Thread newThread(Runnable r) {
                      String maskedRemote = URLUtils.sanitizeURL(remote);
                      return new Thread(r, "CBLPusherSupportExecutor-" + maskedRemote);
                  }
              });
          }
      }
docs: create single thread supportExecutor for push replication