code: func (dbInst *DB) Put(key []byte, value []byte, sync bool) error {
  	wo := dbInst.writeOptsNoSync
  	if sync {
  		wo = dbInst.writeOptsSync
  	}
  	err := dbInst.db.Put(key, value, wo)
  	if err != nil {
  		logger.Errorf("Error writing leveldb key [%#v]", key)
  		return errors.Wrapf(err, "error writing leveldb key [%#v]", key)
  	}
  	return nil
  }
docs: // Put saves the key/value