golang中使用 github.com/coreos/etcd/clientv3 第三方库报错

使用go连接etcd，需要下载第三方库，即：go get go.etcd.io/etcd/clientv3 ，过程中报错如下：

github.com/coreos/etcd/clientv3/balancer/resolver/endpoint
vendorgithub.comcoreosetcdclientv3alancer esolverendpointendpoint.go:114:78: undefined: resolver.BuildOption
vendorgithub.comcoreosetcdclientv3alancer esolverendpointendpoint.go:182:31: undefined: resolver.ResolveNowOption
github.com/coreos/etcd/clientv3/balancer/picker
vendorgithub.comcoreosetcdclientv3alancerpickererr.go:37:44: undefined: balancer.PickOptions
vendorgithub.comcoreosetcdclientv3alancerpicker oundrobin_balanced.go:55:54: undefined: balancer.PickOptions

原因：需要将grpc1.27.1 替换成grpc1.26.0版本

解决：此时可以点开go.mod文件，将google.golang.org/grpc v1.27.1 *// indirect*更改为 google.golang.org/grpc v1.26.0 *// indirect*。

更改方式

replace (
	google.golang.org/grpc v1.28.0 => google.golang.org/grpc v1.26.0
)

然后再go get即可。