How do I update widgets?

In Xamarin.Forms, each Page or Element is a stateful class,
that has properties and methods.
You update your Element by updating a property,
and this is propagated down to the native control.

In Flutter, Widgets are immutable and you can’t directly update them
by changing a property, instead you have to work with the widget’s state.

This is where the concept of Stateful vs Stateless widgets comes from.
A StatelessWidget is just what it sounds like—
a widget with no state information.

StatelessWidgets are useful when the part of the user interface
you are describing doesn’t depend on anything
other than the configuration information in the object.

For example, in Xamarin.Forms, this is similar
to placing an Image with your logo.
The logo is not going to change during runtime,
so use a StatelessWidget in Flutter.