code: func (db *DB) FlushAll() (drop int64, err error) {
  	all := [...](func() (int64, error)){
  		db.flush,
  		db.lFlush,
  		db.hFlush,
  		db.zFlush,
  		db.sFlush}
  
  	for _, flush := range all {
  		n, e := flush()
  		if e != nil {
  			err = e
  			return
  		}
  
  		drop += n
  	}
  
  	return
  }
docs: // func (db *DB) IsAutoCommit() bool {
  // 	return db.status == DBAutoCommit
  // }
  // FlushAll flushes the data.