title: How do I receive the default value of a form control in my custom control (ControlValueAccessor)
body: <p>Let's say I have a form like this:</p>
  
  <pre><code>this.form = fb.group({
          genders: [['MALE']],
      });
  </code></pre>
  
  <p>And I've implemented my own custom form control which implements the ControlValueAccessor interface. I understand that we have the <code>writeValue</code> method, but this method is only called when using either <code>setValue</code> or <code>patchValue</code>. How do I get the default value which was set in the <code>FormBuilder</code>'s <code>group</code> method?</p>