verifying github.com/gorilla/websocket@v1.4.1/go.mod: github.com/gorilla/websocket@v1.4.1/go.mod: Get https://sum.golang.org/lookup/gi thub.com/gorilla/websocket@v1.4.1: dial tcp 172.217.24.17:443: connectex: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond. ————————————————
原因是1.13之后設置了默認的GOSUMDB=sum.golang.org，由於牆的原因無法訪問，執行以下命令關閉即可：
go env -w GOSUMDB=off