title: Wait for initialization of lazy loaded state
body: <p>I have a button and an <code>onClick</code> handler. The first think I do in the <code>onClick</code> handler is</p>
  
  <pre><code>if (this.state.lazyLoadedData === undefined) {
      await this.loadData();
  }
  </code></pre>
  
  <p>My problem is that if I click the button two times quickly, <code>this.loadData()</code> get's executed twice.</p>
  
  <p>What is the typescript/react idiomatic way of solving this?</p>