koa rt. can be custom with microtime.
var koa = require('koa');
var rt = require('koa-rt');
var app = koa();
app.use(rt());
app.use(function *(next){
yield sleep(150);
this.body = 'Hello';
});
function sleep(ms) {
return function(done){
setTimeout(done, ms);
};
}
app.listen(7001);
console.log('listening on port 7001');
MIT