The current Flutter plugin works with IntelliJ 2018.3 and 2019.1 (stable), and with Android Studio 3.3.2 (stable) and 3.4 beta.
The Flutter Inspector and Performance views are only useful when a Flutter app is running. They won’t be visible anymore until an app has started running. They aren’t entirely gone; you can see placeholders surrounding the Flutter Inspector item in the Views menu under Tool Windows.
Many issues were fixed. A full list is in the change log, and is visible in the plugin description.
During release testing we discovered that creating a project with sample code is not working with the master channel of Flutter. We’ll get this fixed in the next patch but for now samples only work with the stable channel of Flutter.