Function hurray_buffer_handoff_event 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn hurray_buffer_handoff_event(
    buffer: *const HurrayBuffer,
    payload: *const HurraySyncEventPayload,
) -> HurrayStatus

Validates an Event-mode sync handoff from producer to consumer.

Checks that:

• The buffer’s declared sync mode is SyncMode::Event.
• payload.sync_handle is non-null.
• payload.event_release_fn is non-null.
• payload.sync_handle_device_tag matches the buffer’s declared device tag.

Returns HURRAY_OK if all checks pass; HURRAY_ERR_SYNC_MODE_MISMATCH otherwise.

Safety

buffer and payload MUST be valid, non-null pointers pointing to live objects.