code: func (db *nodeDB) storeInt64(key []byte, n int64) error {
  	blob := make([]byte, binary.MaxVarintLen64)
  	blob = blob[:binary.PutVarint(blob, n)]
  	return db.lvl.Put(key, blob, nil)
  }
docs: // storeInt64 update a specific database entry to the current time instance as a
  // unix timestamp.