You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: balancer.go
    path of file: ./repos/goldfish/vendor/google.golang.org/grpc
    
    the code of the file until where you have to start completion: /*
 *
 * Copyright 2016, Google Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with o
    
func (rr *roundRobin) Start(target string, config BalancerConfig) error {
	rr.mu.Lock()
	defer rr.mu.Unlock()
	if rr.done {
		return ErrClientConnClosing
	}
	if rr.r == nil {
		// If there is no name resolver installed, it is not needed to
		// do name resolution. In this case, target is added into rr.addrs
		// as the only address available and rr.addrCh stays nil.
		rr.addrs = append(rr.addrs, &addrInfo{addr: Address{Addr: target}})
		return nil
	}
	w, err := rr.r.Resolve(target)
	if err != nil {
		return err
	}
	rr.w = w
	rr.addrCh = make(chan []Address)
	go func() {
		for {
			if err := rr.watchAddrUpdates(); err != nil {
				return
			}
		}
	}()
	return nil
}