Function mi_unwrapped_malloc 

pub unsafe extern "C" fn mi_unwrapped_malloc(
    size: usize,
    alignment: usize,
) -> *mut c_void

Mirrors mi_unwrapped_malloc (include/mimalloc/memory-events.h): backed directly by the raw OS layer, never by the hooked mi_malloc family. See that header’s “Stable public unwrapped instrumentation allocation path” comment for the full contract.