I suspect this issue may be triggered by the upload of golang-golang-x-sync 0.7.0 to sid. #1071035 is another issue related to code changes in the semaphore implmentation.
in google-api-go, I've found exactly one upstream commit that we don't currently have in debian in the 'support/bundler' package: https://github.com/googleapis/google-api-go-client/commit/8d0b2b5bc50e98e2865818bee89911d3348b43dc The commit message talks about a bugfix in the http/transport, but the commit also update the x/sync package 0.7 and increases a timeout. I wonder whether bumping the timeout would be the thing to do in debian as well? I'll try later when I have a better internet connection.