code: func (c *Cluster) GetStoreByAddr(addr string) *metapb.Store {
  	c.RLock()
  	defer c.RUnlock()
  
  	for _, s := range c.stores {
  		if s.meta.GetAddress() == addr {
  			return proto.Clone(s.meta).(*metapb.Store)
  		}
  	}
  	return nil
  }
docs: // GetStoreByAddr returns a Store's meta by an addr.