安裝golang github.com/hyperledger/fabric-contract-api-go依賴包的時候，長時間無響應，最后報如下錯誤：
go: github.com/hyperledger/fabric-contract-api-go@v1.0.0: Get https://proxy.golang.org/github.com/hyperledger/fabric-contract-api-go/@v/v1.0.0.mod: dial tcp 172.217.27.145:443: i/o timeout
~/fabric-samples/test-network
Finished vendoring Go dependencies
++ peer lifecycle chaincode package fabcar.tar.gz --path ../chaincode/fabcar/go/ --lang golang --label fabcar_1
++ res=1
++ set +x
Error: failed to normalize chaincode path: 'go list' failed with: go: github.com/hyperledger/fabric-contract-api-go@v1.0.0: Get https://proxy.golang.org/github.com/hyperledger/fabric-contract-api-go/@v/v1.0.0.mod: dial tcp 172.217.27.145:443: i/o timeout: exit status 1
!!!!!!!!!!!!!!! Chaincode packaging on peer0.org1 has failed !!!!!!!!!!!!!!!!
ERROR !!! Deploying chaincode failed
解決辦法
使用七牛雲 go module 鏡像
golang1.13.x 可以直接執行：
go env -w GO111MODULE=on go env -w GOPROXY=https://goproxy.cn,direct
然后再次使用 go get 下載 gin 依賴就可以了。