pub unsafe fn set_allocator(
    new_malloc: Option<unsafe extern "C" fn(_: usize) -> *mut c_void>,
    new_calloc: Option<unsafe extern "C" fn(_: usize, _: usize) -> *mut c_void>,
    new_realloc: Option<unsafe extern "C" fn(_: *mut c_void, _: usize) -> *mut c_void>,
    new_free: Option<unsafe extern "C" fn(_: *mut c_void)>
)