code: func (it *Iterator) RawFind(key []byte) []byte {
  	it.Seek(key)
  	if it.Valid() {
  		k := it.RawKey()
  		if k == nil {
  			return nil
  		} else if bytes.Equal(k, key) {
  			return it.RawValue()
  		}
  	}
  
  	return nil
  }
docs: // Finds by key, if not found, nil returns, else a reference of value returns.
  // you must be careful that it will be changed after next iterate.