title: Angular material tree expand a particular node
body: <p>I have seen various examples to expand all nodes in mat-tree using</p>
  
  <pre><code>expandAll()
  </code></pre>
  
  <p>Is there any mechanism to expand a particular node if we click on it. Something like</p>
  
  <pre><code>node.expand()
  </code></pre>
  
  <p>I had referred angular material documentation but not got any answer. Please guide if anyone gone through it.</p>