compareAndSetFiberCaptureFunction

fun compareAndSetFiberCaptureFunction(oldValue: (A_Fiber) -> Unit?, newValue: (A_Fiber) -> Unit?): Boolean

Attempt to write the newValue into the newFiberHandler, but only if it currently contains oldValue. Answer whether it wos successful. If it was not successful due to the oldValue not being the current value, make no change and answer false.