how to make a search button in flutter code example

Example: search button design in flutter

Container(
  height: 51,
  child: Row(
    children: [
      Expanded(
        child: TextField(
          decoration: InputDecoration(
            prefixIcon: Icon(Icons.search),
            hintText: "Search",
            border: OutlineInputBorder(
                borderRadius: BorderRadius.circular(15.0),
                borderSide: BorderSide.none),
            fillColor: Color(0xffe6e6ec),
            filled: true,
          ),
        ),
      ),
      SizedBox(width: 15),
      Container(
        decoration: BoxDecoration(
          color: Color(0xffe6e6ec),
          borderRadius: BorderRadius.circular(9.0),
        ),
        child: IconButton(
          icon: Icon(Icons.tune),
          onPressed: () {
            Provider.of(context)
                .changeState();
          },
        ),
      ),
    ],
  ),
),