async function handleAsset(meta, res, isModule) {
	let code = '';
	let type = null;

	if (isModule) {
		type = 'application/javascript;charset=utf-8';
		const specifier = JSON.stringify('/@npm/' + meta.specifier + '?asset');
		code = `import{style}from '/_wmr.js';\nstyle(${specifier});`;
	} else {
		type = getMimeType(meta.path);
		code = await loadPackageFile(meta);
	}
	res.writeHead(200, {
		'content-type': type || 'text/plain',
		'content-length': Buffer.byteLength(code)
	});
	res.end(code);
}
Serve a "proxy module" that uses the WMR runtime to load CSS.
@param {ReturnType<typeof normalizeSpecifier>} meta
@param {import('http').ServerResponse} res
@param {boolean} [isModule]