Android Studio - Flutter Plugin - Moving method to another file by refactoring

Question

Why I cannot (?) move a method from one Dart file to another using Android Studio and Flutter Plugin? My file is getting big and I decided to refactor it by separated some Widget build methods to their own files. I started by selecting one of the methods, performing the Android Studio's refactor command and click move as I always did with java. But looks like the only option is to move the actual Dart File to another Directory.

It would be nice if I could move the method and the entire tree to another file, and some others refactoring options.

Is there any way to facilitate this type of refactoring?

Android Studio 3.3 RC 2 Build #AI-182.5107.16.33.5160847, built on December 3, 2018 JRE: 1.8.0_152-release-1248-b01 amd64 JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o Linux 4.15.0-39-generic

Solution

This is a open feature request of the dart sdk. Unfortunately, for more than two years it did not find much attention. https://github.com/dart-lang/sdk/issues/30310