code: boolean flush() {
      if (!dirty)
        return true;
  
      acquireExclusiveLock();
      try {
  
        final long timer = OProfiler.getInstance().startChrono();
  
        // FORCE THE WRITE OF THE BUFFER
        for (int i = 0; i < FORCE_RETRY; ++i) {
          try {
            buffer.force();
            dirty = false;
            break;
          } catch (Exception e) {
            OLogManager.instance().debug(this,
                "Cannot write memory buffer to disk. Retrying (" + (i + 1) + "/" + FORCE_RETRY + ")...");
            OMemoryWatchDog.freeMemory(FORCE_DELAY);
          }
        }
  
        if (dirty)
          OLogManager.instance().debug(this, "Cannot commit memory buffer to disk after %d retries", FORCE_RETRY);
        else
          OProfiler.getInstance().updateCounter("system.file.mmap.pagesCommitted", 1);
  
        OProfiler.getInstance().stopChrono("system.file.mmap.commitPages", timer);
  
        return !dirty;
  
      } finally {
        releaseExclusiveLock();
      }
    }
docs: Flushes the memory mapped buffer to disk only if it's dirty.
  
  @return true if the buffer has been successfully flushed, otherwise false.