由于众所周知的原因，在终端下载golang依赖包会出现类似下面的提示：
go: cloud.google.com/go@v0.26.0: unrecognized import path "cloud.google.com/go" (https fetch: Get https://cloud.google.com/go?go-get=1: dial tcp 216.58.200.238:443: I/O timeout)
go: error loading module requirements解决方法：
主要使用go mod的replace方法，在go.mod文件中将被墙的包，重定向到github上；当然也可以下载到本地，然后使用本地路径来指定被墙的包
replace golang.org/x/net => github.com/golang/net latest
replace golang.org/x/tools => github.com/golang/tools latest
replace golang.org/x/crypto => github.com/golang/crypto latest
replace golang.org/x/sys => github.com/golang/sys latest
replace golang.org/x/text => github.com/golang/text latest
replace golang.org/x/sync => github.com/golang/sync latest
replace golang.org/x/exp => github.com/golang/exp latest
replace golang.org/x/lint => github.com/golang/lint latest
replace golang.org/x/oauth2 => github.com/golang/oauth2 latest
replace golang.org/x/time => github.com/golang/time latest
replace golang.org/x/image => github.com/golang/image latest
replace golang.org/x/mobile => github.com/golang/mobile latest
replace cloud.google.com/go => github.com/googleapis/google-cloud-go latest
replace google.golang.org/grpc => github.com/grpc/grpc-go latest
replace google.golang.org/appengine => github.com/golang/appengine latest
replace google.golang.org/genproto => github.com/googleapis/go-genproto latest
replace google.golang.org/api => github.com/googleapis/google-api-go-client latest
