cmd/autogazelle/server_unix.go
func recordWrite(path string) {
	dirSetMutex.Lock()
	defer dirSetMutex.Unlock()
	dirSet[path] = true
}
func recordWrite(path string) {
	dirSetMutex.Lock()
	defer dirSetMutex.Unlock()
	dirSet[path] = true
}
// recordWrite records that a directory has been modified and that its build
// file should be updated the next time gazelle runs.