Storage

    pub const Storage = union {
        unused: List.DoubleNode,
        submission: Submission,
        pending: Pending,
        completion: Completion,

        pub const Submission = struct {
            node: List.SingleNode,
            operation: Operation,
        };

        pub const Pending = struct {
            node: List.DoubleNode,
            tag: Tag,
            userdata: Userdata align(@max(@alignOf(usize), 4)),

            pub const Userdata = [7]usize;
        };

        pub const Completion = struct {
            node: List.SingleNode,
            result: Result,
        };
    }