https://stackoverflow.com/questions/35282928/how-do-i-set-a-timeout-for-utilsdownload-file-in-r
getOption(‘timeout‘) # [1] 60 options(timeout=100)
https://www.codenong.com/26086134/
getOption("repos") options(repos=c(CRAN="@CRAN@", CRANextra="http://www.stats.ox.ac.uk/pub/RWin"))
原文：https://www.cnblogs.com/BlueBlueSea/p/13950041.html