Function split_chain_mpsc 

pub unsafe fn split_chain_mpsc(
    pool: *mut SlotPoolLayout,
    queue: *mut MpscQueue,
) -> (ChainMpscProducer, ChainMpscConsumer)

Create MPSC producer/consumer handles over a shared slot pool and a specific MPSC queue.

Safety

The caller must ensure:

• pool and queue point into a valid, initialized, mapped region.
• The mapping outlives all returned handles.
• Exactly one thread uses the consumer at a time.
• Producer handles may be used concurrently.