title: how to create empty constructor in dart?
body: <p>Here I want to create an empty constructor to print <em>empty constructor is called</em> message but it shows try adding initializer error.</p>
  <pre><code>class ReusableCard extends StatelessWidget {
    final Color color;
  
    ReusableCard(){    
  print('empty const is called');   
   }
  
    ReusableCard(this.color);
  
    @override   Widget build(BuildContext context) {
      return Container(
        margin: EdgeInsets.all(15.0),
        //TODO:use decorator only if colors are added inside in it.
  
        decoration: BoxDecoration(
          color: Color(0xFF1D1E20),
          borderRadius: BorderRadius.circular(10.0),
        ),
        // width: 100,
        height: 100,
      );   
  }
  }
  </code></pre>