getSize() {
		if (!this.lazy) return -1;
		const options =
			/** @type {{ options: { size?: number } }} */
			(this.lazy).options;
		if (!options) return -1;
		const size = options.size;
		if (typeof size !== "number") return -1;
		return size;
	}
@returns {number} size of the content or -1 if not known