As an etcd user on the latest version, I want to evaluate this tool but unfortunately it won't build

[m0un10]

Reproduce steps:

% gh repo clone rekby/etcddir
Cloning into 'etcddir'...
remote: Enumerating objects: 101, done.
remote: Total 101 (delta 0), reused 0 (delta 0), pack-reused 101
Receiving objects: 100% (101/101), 19.69 KiB | 3.94 MiB/s, done.
Resolving deltas: 100% (50/50), done.

% go mod init github.com/rekby/etcddir
go: creating new go.mod: module github.com/rekby/etcddir

% go build
go: finding module for package golang.org/x/net/context
go: finding module for package github.com/rjeczalik/notify
go: finding module for package github.com/coreos/etcd/clientv3
go: finding module for package github.com/coreos/etcd/client
go: downloading github.com/rjeczalik/notify v0.9.2
go: downloading golang.org/x/net v0.0.0-20201207224615-747e23833adb
go: downloading github.com/coreos/etcd v3.3.25+incompatible
go: found github.com/coreos/etcd/client in github.com/coreos/etcd v3.3.25+incompatible
go: found github.com/rjeczalik/notify in github.com/rjeczalik/notify v0.9.2
go: found golang.org/x/net/context in golang.org/x/net v0.0.0-20201207224615-747e23833adb
go: finding module for package github.com/json-iterator/go
go: finding module for package google.golang.org/grpc
go: finding module for package google.golang.org/grpc/codes
go: finding module for package github.com/google/uuid
go: finding module for package google.golang.org/grpc/metadata
go: finding module for package google.golang.org/grpc/status
go: finding module for package google.golang.org/grpc/keepalive
go: finding module for package google.golang.org/grpc/grpclog
go: finding module for package go.uber.org/zap
go: finding module for package github.com/coreos/pkg/capnslog
go: downloading google.golang.org/grpc v1.34.0
go: finding module for package google.golang.org/grpc/resolver
go: downloading go.uber.org/zap v1.16.0
go: downloading github.com/google/uuid v1.1.2
go: finding module for package github.com/modern-go/reflect2
go: finding module for package github.com/golang/protobuf/proto
go: finding module for package google.golang.org/grpc/credentials
go: finding module for package google.golang.org/grpc/resolver/passthrough
go: finding module for package github.com/coreos/go-semver/semver
go: finding module for package github.com/coreos/go-systemd/journal
go: finding module for package google.golang.org/grpc/balancer
go: finding module for package github.com/gogo/protobuf/gogoproto
go: finding module for package google.golang.org/genproto/googleapis/api/annotations
go: finding module for package google.golang.org/grpc/connectivity
go: downloading github.com/golang/protobuf v1.4.3
go: finding module for package google.golang.org/grpc/resolver/dns
go: finding module for package go.uber.org/zap/zapcore
go: downloading google.golang.org/genproto v0.0.0-20201207150747-9ee31aac76e7
go: found github.com/json-iterator/go in github.com/json-iterator/go v1.1.10
go: found github.com/modern-go/reflect2 in github.com/modern-go/reflect2 v1.0.1
go: found github.com/coreos/pkg/capnslog in github.com/coreos/pkg v0.0.0-20180928190104-399ea9e2e55f
go: found github.com/google/uuid in github.com/google/uuid v1.1.2
go: found go.uber.org/zap in go.uber.org/zap v1.16.0
go: found google.golang.org/grpc in google.golang.org/grpc v1.34.0
go: found github.com/coreos/go-semver/semver in github.com/coreos/go-semver v0.3.0
go: found github.com/gogo/protobuf/gogoproto in github.com/gogo/protobuf v1.3.1
go: found github.com/golang/protobuf/proto in github.com/golang/protobuf v1.4.3
go: found google.golang.org/genproto/googleapis/api/annotations in google.golang.org/genproto v0.0.0-20201207150747-9ee31aac76e7
go: found github.com/coreos/go-systemd/journal in github.com/coreos/go-systemd v0.0.0-20191104093116-d3cd4ed1dbcf
# github.com/coreos/etcd/clientv3/balancer/resolver/endpoint
../../../../go/pkg/mod/github.com/coreos/[email protected]+incompatible/clientv3/balancer/resolver/endpoint/endpoint.go:114:78: undefined: resolver.BuildOption
../../../../go/pkg/mod/github.com/coreos/[email protected]+incompatible/clientv3/balancer/resolver/endpoint/endpoint.go:182:31: undefined: resolver.ResolveNowOption
# github.com/coreos/etcd/clientv3/balancer/picker
../../../../go/pkg/mod/github.com/coreos/[email protected]+incompatible/clientv3/balancer/picker/err.go:37:44: undefined: balancer.PickOptions
../../../../go/pkg/mod/github.com/coreos/[email protected]+incompatible/clientv3/balancer/picker/roundrobin_balanced.go:55:54: undefined: balancer.PickOptions