src/vs/workbench/contrib/notebook/common/notebookCommon.ts/generate
	export function generate(notebook: URI, handle: number): URI {

		const s = handle.toString(_radix);
		const p = s.length < _lengths.length ? _lengths[s.length - 1] : 'z';

		const fragment = `${p}${s}s${encodeBase64(VSBuffer.fromString(notebook.scheme), true, true)}`;
		return notebook.with({ scheme, fragment });
	}