title: React.createRef always null
body: <p>I am probably doing something really stupid here, but for the life of me, I cannot figure out why <code>ref</code> is always null.</p>
  
  <pre><code>import React, { PureComponent } from 'react';
  
  class MyComponent extends PureComponent {
    constructor(props) {
      super(props);
      this.myRef = React.createRef();
      console.log(this.myRef);
    }
  
    componentDidMount() {
      console.log(this.myRef);
    }
  
    componentWillUnmount() {
      console.log('unmounting');
    }
  
    render() {
      console.log(this.myRef);
      return (
        &lt;div ref={this.myRef}&gt;
          foobar
        &lt;/div&gt;
      );
    }
  }
  </code></pre>
  
  <p>Console:</p>
  
  <pre><code>{current: null}
  {current: null}
  {current: null}
  </code></pre>
  
  <p>I am on React 16.3. What am I missing?</p>