yield this.render('index') call error Error: write EPIPE
my code:

```
    app.get('/', function* (next) {
         yield this.render('../index.html')
    });
```

when my iPhone visite the website, terminal report 

```
    Error: write EPIPE
       at exports._errnoException (util.js:890:11)
       at WriteWrap.afterWrite (net.js:769:14)
```
