gpuUnavailableReason function
Why Flutter GPU can't be used here, or null when it can.
Tests that render call this first and skip when it returns a reason, so a
plain flutter test stays green. Run them with
flutter test --enable-impeller --enable-flutter-gpu --tags gpu.
Implementation
String? gpuUnavailableReason() {
try {
gpu.gpuContext;
return null;
} on Object catch (e) {
return '$e';
}
}