Struct Slot 

#[repr(C)]
pub struct Slot {
    pub next_free: IndexbusAtomicU32,
    pub refcnt: IndexbusAtomicU32,
    pub len: u32,
    pub pad: u32,
    pub data: [u8; 256],
}

Fixed-size message slot.

Slots are reference-counted and stored in shared memory; queues hold slot indices.

Fields

next_free: IndexbusAtomicU32

Next slot in the free list (slot index), or crate::INDEXBUS_EMPTY_FREE_U32.

refcnt: IndexbusAtomicU32

Reference count for shared ownership across queues/consumers.

len: u32

Payload length in bytes.

pad: u32

Padding (reserved).

data: [u8; 256]

Payload storage.