Kotlin - Form feed character - Illegal escape: '\f'

Kotlin does not support the escape "\f" (Form Feed Character). So what is the proper way port "\f" from java to Kotlin?

Java:

String str = "\f"; // OK

Kotlin:

var str = "\f"  // Illegal escape: '\f'

Anyway, that looked like a bug to me because Kotlin and java should work well together.