Function fanout_handles 

pub fn fanout_handles<const N: usize>(
    shared: &SharedFanoutLayoutCell<N>,
    consumer: usize,
) -> Result<(FanoutProducer<N>, FanoutRouter<N>, FanoutConsumer<N>), Error>

Create handles over a fanout layout.

Returns Err if the region is not initialized or is not v1-compatible.

The returned handles borrow the region by raw pointer; the caller must keep the underlying SharedFanoutLayout<N> alive (and mapped) for as long as the handles are used.