mapbox/tilemill — comment on commit 9cfd9326bb71f98cb494ce9ccc1933ef36b2e656
File:  line 0
By lxbarth:

`resp.on('end', callback);` triggers a fatal error just like [1] when S3 reports an error. To test append a random string to `uploadArgs.policy`.

[1] http://stackoverflow.com/questions/7813847/nodejs-amazon-upload-using-knox-crashing-at-assertion-error