func bridge<T>(obj: T) -> UnsafeMutableRawPointer Convert to void* without ownership, only use when lifetime of object is guaranteed elsewhere
func bridge<T>(ptr: UnsafeRawPointer ) -> T Convert from void* without ownership, only use when lifetime of object is guaranteed elsewhere
func bridgeTransfer <T>(ptr: UnsafeRawPointer ) -> T Convert from void* with ownership, make sure these are always called in matching pairs with bridgeRetained