Note:

If you do not see a Flutter version number or device info,
your project might not have been detected as a Flutter project.
Ensure that the folder that contains your pubspec.yaml is
inside a VS Code Workspace Folder.

If the status bar reads No Devices, Flutter has not been
able to discover any connected iOS or Android devices or simulators.
You need to connect a device, or start a simulator or emulator,
to proceed.

The Flutter extension automatically selects the last device connected.
However, if you have multiple devices/simulators connected, click
device in the status bar to see a pick-list
at the top of the screen. Select the device you want to use for
running or debugging.

Are you developing for macOS or iOS remotely using
  Visual Studio Code Remote? If so, you might need to manually
  unlock the keychain. For more information, see this
  question on StackExchange.

Run app without breakpoints