docs: public File getNextFile(File pre) {
          try {
              lock.lockInterruptibly();
              if (exception != null) {
                  throw exception;
              }
  
              if (binlogs.size() == 0) {
                  return null;
              } else {
                  if (pre == null) {// 第一次
                      return binlogs.get(0);
                  } else {
                      int index = seek(pre);
                      if (index < binlogs.size() - 1) {
                          return binlogs.get(index + 1);
                      } else {
                          return null;
                      }
                  }
              }
          } catch (InterruptedException e) {
              Thread.currentThread().interrupt();
              return null;
          } finally {
              lock.unlock();
          }
      }