Content-length error prevents page load and leads lint error

I get this error always:

```
Unexpected error while processing request: Content-Length header was 1747, but should be 1757
/Users/alexd/.rbenv/versions/2.1.1/lib/ruby/gems/2.1.0/gems/rack-1.5.2/lib/rack/lint.rb:631:in `verify_content_length'
```

If my post is very small, I get it with some types of characters like `"` but they are all UTF-8 plain text.

When I fix all the character issues, I still get the error when trying to display the whole post.

Start by reproducing the UTF-8 character case and the full-post response, then inspect Rack 1.5.2 at lib/rack/lint.rb:631, where the Content-Length check raises the error. Trace the Toto response that supplies the length; done means both small posts containing characters such as quotation marks and full posts load without Rack lint errors.

Written by the indexing model from the issue text.