$ open -a simulator
              
              On Windows or Linux, it’s not possible to launch an iOS simulator.
            
          
          
            To setup a real device, follow the device-specific instructions
on the Install page for your OS.

Invoke Run > Start Debugging or press F5.

Wait for the app to launch—progress is printed
in the Debug Console view.

After the app build completes, you’ll see the starter app on your device.

Try hot reload

Flutter offers a fast development cycle with Stateful Hot Reload,
the ability to reload the code of a live running app without
restarting or losing app state.
Make a change to app source,
tell your IDE or command-line tool that you want to hot reload,
and see the change in your simulator, emulator, or device.

Open lib/main.dart.

Change the string

        'You have pushed the button this many times'