Great to see built-in support for BigInt, Date, and Uint8Array! I've noticed that Infinity and NaN serialize to null - maybe it's worth giving it the same special treatment like `undefined`? E.g.: ```js import {serialize} from "capnweb"; console.log(serialize(Number.NaN)); // null console.log(serialize(Number.POSITIVE_INFINITY)); // null console.log(serialize(undefined)); // ["undefined"] ```