std::alloc::__default_lib_allocator

Function __rdl_realloc

Source 
pub unsafe extern "C" fn __rdl_realloc(
    ptr: *mut u8,
    old_size: usize,
    align: usize,
    new_size: usize,
) -> *mut u8
🔬This is a nightly-only experimental API. (alloc_internals)