∀ {α : Type u} {β : α → Type v} [inst : BEq α] [inst_1 : Hashable α] [inst_2 : SizeOf α]
  [inst_3 : (a : α) → SizeOf (β a)] (inner : Std.DHashMap.Raw α β) (wf : inner.WF),
  sizeOf { inner := inner, wf := wf } = 1 + sizeOf inner + sizeOf wf