Which operating system (GOOS) and version are you using?

#  sw_vers
ProductName:    Mac OS X
ProductVersion: 10.13.6
BuildVersion:   17G65

# go version
go version go1.10.3 darwin/amd64

Please describe the issue that occurred.

During CI-Build for pr #263 the tests on MacOS failed with a RaceCondition. I tried to reproduce locally and reran the tests around a dozen times and noticed two things:

• TestExchangedataInWatchedDir and TestExchangedataInWatchedFile fail entirely on my machine ("integration_darwin_test.go:92: [1] exchangedata failed: operation not supported").
• TestFsnotifyDeleteWatchedDir has flakes. It worked like 75% of the times in my tests. This is also the test that failed in the CI build.

Are you able to reproduce the issue? Please provide steps to reproduce and a code sample if possible.

I just ran go test -v --race ./... and the first issue shows all the time, the second only every now and then.