func CallErr(f func() error) error {
	checkRun()
	errChan := make(chan error)
	callQueue <- func() {
		errChan <- f()
	}
	return <-errChan
}
func CallErr(f func() error) error {
	checkRun()
	errChan := make(chan error)
	callQueue <- func() {
		errChan <- f()
	}
	return <-errChan
}
func CallErr ( f func ( ) error ) error { checkRun ( ) errChan := make ( chan error ) callQueue <- func ( ) { errChan <- f ( ) } return <- errChan }
// CallErr queues function f on the main thread and returns an error returned by f.
CallErr queues function f on the main thread and returns an error returned by f .