Function mi_theap_malloc_csize 

pub unsafe fn mi_theap_malloc_csize(
    theap: *mut mi_theap_t,
    size: size_t,
) -> *mut c_void

Allocate from a thread-local heap when the size is statically known.

This mirrors mimalloc’s inline mi_theap_malloc_csize helper.

Safety

theap must be non-null and valid for the calling thread. The returned pointer must be checked for null and freed with a compatible mimalloc free API.