code: public void addFile(int level, long fileNumber,
              long fileSize,
              InternalKey smallest,
              InternalKey largest)
      {
          FileMetaData fileMetaData = new FileMetaData(fileNumber, fileSize, smallest, largest);
          addFile(level, fileMetaData);
      }
docs: REQUIRES: "smallest" and "largest" are smallest and largest keys in file