title: Custom view decorations in VSCode extension
body: <p>I'm building a VS Code extension and it uses a <code>TreeDataProvider</code> to create a list of items. The list has nested children and I would like to show a count for these in the parent.</p>
  
  <p>I've looked for examples and tried to understand how the git extension does it but no luck. Perhaps someone can provide an example of how to do this.</p>
  
  <p><img src="https://i.stack.imgur.com/q7qOj.png" alt="Count example in GIT extension"></p>
  
  <p><img src="https://i.stack.imgur.com/oQKDg.png" alt="Count example in file explorer"></p>