title: flutter container remove outline border shadow
body: <p>I want to remove this colored line of pixel rounded in <code>IconButton</code>
  I think this line of pixel didn't relate of shadow</p>
  <p><img src="https://i.stack.imgur.com/HyiUQ.png" alt="enter image description here" /></p>
  <p>My code is:</p>
  <pre><code>Container(
      boxShadow: [
        BoxShadow(
          color: Colors.transparent,
        ),
      ],
      color: Colors.black,
      shape: BoxShape.circle,
      border: Border.all(
        color: Colors.white,
        width: 5,
      ),
    ),
    child: IconButton(
      color: Colors.white,
      icon: Icon(
         Icons.search,
      ),
    ),
  ),
  </code></pre>