title: Omit fields when printing Protobuf message
body: <p>Is it possible to choose what fields or at least what field types to be considered when calling <code>message.DebugString()</code> in Google Protobuf?</p>
  
  <p>I have the following message description:</p>
  
  <pre><code>message Message
  {
      optional string name = 1
      optional int32 blockSize = 2;
      optional bytes block = 3;
  }
  </code></pre>
  
  <p>I only want to print <code>name</code> and <code>blockSize</code> and omit the <code>block</code> field, which happens to be large (e.g.: 64KB) and its content is insignificant.</p>
  
  <p>I built a method that specifically adds to a <code>std::stringstream</code> only the fields of interest but it seems that I have to modify the method for every change in message description.</p>