src/vs/base/node/zip.ts/buffer
export function buffer(zipPath: string, filePath: string): Promise<Buffer> {
	return read(zipPath, filePath).then(stream => {
		return new Promise<Buffer>((c, e) => {
			const buffers: Buffer[] = [];
			stream.once('error', e);
			stream.on('data', (b: Buffer) => buffers.push(b));
			stream.on('end', () => c(Buffer.concat(buffers)));
		});
	});
}