docs: private void checkCapacity() {
          if (memoryQueue.size() > maxMemoryLogSize) {
              // 超过阀值,需要批量刷盘
              if (flushing.compareAndSet(false, true)) {
                  // 这里可以采用new Thread, 因为这里只会同时new一个
                  new Thread(new Runnable() {
                      @Override
                      public void run() {
                          try {
                              checkAndFlush();
                          } catch (Throwable t) {
                              LOGGER.error("Capacity full flush error", t);
                          }
                      }
                  }).start();
              }
          }
      }