title: Fix warning "Capturing [an object] strongly in this block is likely to lead to a retain cycle" in ARC-enabled code
body: <p>In ARC enabled code, how to fix a warning about a potential retain cycle, when using a block-based API?</p>
  
  <p>The warning:<br>
  <code>Capturing 'request' strongly in this block is likely to lead to a retain cycle</code></p>
  
  <p>produced by this snippet of code:  </p>
  
  <pre><code>ASIHTTPRequest *request = [[ASIHTTPRequest alloc] initWithURL:...
  
  [request setCompletionBlock:^{
      NSDictionary *jsonDictionary = [[CJSONDeserializer deserializer] deserialize:request.rawResponseData error:nil];
      // ...
      }];
  </code></pre>
  
  <p>Warning is linked to the use of the object <code>request</code> inside the block.</p>