"boring">fn main() {
</span>fn init_backup_heap(
    boot_info: &amp;mut BootInfo,
    page_table: &amp;mut OffsetPageTable&lt;'static&gt;,
) -&gt; (usize, MemoryRegion, Option&lt;PhysFrame&gt;) {
    // omitted: Initialize virtual memory regions for the backup heap.

    // Initialize.
    // Enable heap allocator.
    unsafe {
        awkernel_lib::heap::init_backup(HEAP_START, BACKUP_HEAP_SIZE);
        awkernel_lib::heap::TALLOC.use_primary_then_backup();
    }

    (backup_pages, backup_heap_region, ne