go mod 包依赖自动管理模块3-终极篇

lixiaomei:go_work limeihui$ go env
GO111MODULE="on"
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/limeihui/Library/Caches/go-build"
GOENV="/Users/limeihui/Library/Application Support/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOINSECURE=""
GOMODCACHE="/Users/limeihui/Documents/go_work/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/limeihui/Documents/go_work"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"      //Mac竟然不需要配置代理，，歧视
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/darwin_amd64"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/2f/f33qpdds5992h3c4nv5qclk80000gn/T/go-build323116324=/tmp/go-build -gno-record-gcc-switches -fno-common"
lixiaomei:go_work limeihui$