I have a button in my app like

And below is the code for the same
Widget loginButtonChild = const Text(
"Log in",
style: TextStyle(
color: Colors.white,
fontFamily: "OpenSans-Regular",
),
);
FlatButton.icon(
shape: RoundedRectangleBorder(
borderRadius: new BorderRadius.circular(18.0),
side: BorderSide(color: Colors.red)),
color: Colors.red,
label: loginButtonChild,
icon: Icon(Icons.arrow_forward ),
onPressed: () {
//some function
},
)
I am trying to create a button something like

Can anyone help in this or any suggestions?