title: NSAttributedString initWithData:options:documentAttributes:error: is executing very slowly
body: <p>I was trying out the new iOS 7 APIs, and the following code would take over a minute to execute!</p>
  
  <pre><code>NSLog(@"start encoding");
  NSString *htmlBody = @"&lt;html&gt;&lt;body&gt;I am &lt;b&gt;bold&lt;/b&gt; and &lt;i&gt;italic&lt;/i&gt;";
  NSStringEncoding encoding = NSUnicodeStringEncoding;
  NSData *data = [htmlBody dataUsingEncoding:encoding];
  NSDictionary *options = @{NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType,
                            NSCharacterEncodingDocumentAttribute: @(encoding)};
  
  NSAttributedString *body = [[NSAttributedString alloc] initWithData:data
                            options:options
                            documentAttributes:nil
                            error:nil];
  
  NSLog(@"end encoding%@", body);
  </code></pre>
  
  <p>What is going on?</p>