levelup vs. level-sublevel binary stream

index.js

var server = require('http').createServer(handler).listen(function () { console.log(this.address()); });
var fs = require('fs');
var levelup = require('level');
var subLevel = require('level-sublevel');
var dbPath = './test';
if (!fs.existsSync(dbPath)) {
    fs.mkdirSync(dbPath);
}

var db = subLevel(levelup(dbPath));
var levelNames = ['wow', 'such', 'content'];
var subLevels = levelNames.reduce(function (obj, name) {
    obj[name] = db.sublevel(name, { valueEncoding: 'json' });
    obj[name].ws = obj[name].createWriteStream({ type: 'put', valueEncoding: 'json' });
    obj[name].ws.write({ key: Date.now(), value: { foo: 'bar', bar: 'baz' } });
    return obj;
}, {});
db.put(Date.now(), { foo: 'bar', bar: 'baz' }, { valueEncoding: 'json' });

// get /levelup to read from the top level, otherwise a random sublevel is selected
function handler(req, res) {
    if (req.url === '/' || req.url === '/levelup') {
        res.writeHead(200, { 'Content-Type': 'application/json' });
        var options = { keys: false, values: true, valueEncoding: 'binary' };
        var rso = (req.url === '/levelup') ? db : subLevels[levelNames[Math.floor(Math.random() * 3)]];
        var rs = rso.createReadStream(options);
        rs.on('data', function (data) { console.log('value from database:', typeof data, data); });
        return rs.pipe(res);
    }
    res.statusCode = 418;
    res.end('all out of coffee...');
}