findMixinImports method
Returns a sorted list of imports needed to support all mixins.
Implementation
List<String> findMixinImports() {
final mixins = <PbMixin>{};
for (final m in messageGenerators) {
m.addMixinsTo(mixins);
}
return mixins
.map((mixin) => mixin.importFrom)
.toSet()
.toList(growable: false)
..sort();
}