Method alloc

kernel/oswrapper/vspace.h:469–471

    return VRef<U>::from_vaddr(vaddr);
  }
  static VRef<T> alloc(size_t n = 1) {
    return VRef<T>(internals::vmem_alloc(n * sizeof(T)));
  }
  void free() {
    as_ptr()->~T(); // explicitly call destructor
    internals::vmem_free(vaddr);