RandomWordState with first load and no rebuild the starter state after setState() invoked

RandomWordsWidget.dart

import 'package:english_words/english_words.dart';
import 'package:flutter/material.dart';

class RandomWords extends StatefulWidget {
  @override
  RandomWordsState createState() => new RandomWordsState();
}

class RandomWordsState extends State<RandomWords> {
  static final List<WordPair> _suggestions = [];
  static final Set<WordPair> _saved = Set<WordPair>();
  static final TextStyle _biggerFont = const TextStyle(fontSize: 18.0);

  @override
  initState(){
    super.initState();
    _suggestions.addAll(createFirstSuggestions());
  }

  static Iterable<WordPair> createFirstSuggestions(){
    return generateWordPairs().take(20);
  }

  Widget _buildSuggestions() {
    print("Rebuild");
    return ListView.builder(
      padding: const EdgeInsets.all(16.0),
      itemBuilder: /*1*/ (context, i) {
        if (i.isOdd) return Divider(); /*2*/

        final index = i ~/ 2; /*3*/
        if (index >= _suggestions.length) {
          _suggestions.addAll(generateWordPairs().take(10)); /*4*/
        }
        return _buildRow(_suggestions[index]);
      },
    );
  }

  Widget _buildRow(WordPair pair){
    final bool alreadySaved = _saved.contains(pair);
    return ListTile (
      title: Text(
        pair.asPascalCase, 
        style: _biggerFont
      ),
      trailing: Icon(
        alreadySaved ? Icons.favorite : Icons.favorite_border,
        color: alreadySaved ? Colors.red: null,
      ),
      onTap : () {
        setState(() {
          alreadySaved ? _saved.remove(pair) : _saved.add(pair);
        });
      }
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Gerador de nomes de Startups"),
        actions: <Widget>[
          IconButton(
            icon: Icon(Icons.list),
            onPressed: _pushSaved,
          ),
        ],
      ),
      body: _buildSuggestions()
    );
  }

  void _pushSaved(){
    Navigator.of(context).push(
      MaterialPageRoute<void>(
        builder: (BuildContext context){

          final Iterable<ListTile> tiles = _saved.map(
            (WordPair pair){
              return ListTile(
                title: Text(
                  pair.asPascalCase,
                  style: _biggerFont,
                )
              );
            }
          );

          final List<Widget> divided = ListTile.divideTiles(
            context: context,
            tiles: tiles
          ).toList();

          return Scaffold(
            appBar: AppBar(
              title: Text("Sugestões salvas")
            ),
            body: ListView(children: divided)
          );
        }
      )
    );
  }
}