title: Flutter Error: A non-null value must be returned since the return type 'Widget' doesn't allow null
body: <p>Launching lib\main.dart on F8331 in debug mode...
  Running Gradle task 'assembleDebug'...
  ../../Documents/Android%20Studio%20Project/kotaawan/lib/feature/main/home/product/new-product.dart:37:22: Error: A non-null value must be returned since the return type 'Widget' doesn't allow null.</p>
  <ul>
  <li>'Widget' is from 'package:flutter/src/widgets/framework.dart' ('/E:/flutter/packages/flutter/lib/src/widgets/framework.dart').
  builder: (BuildContext context, AsyncSnapshot snapshot) {
  ^
  ../../Documents/Android%20Studio%20Project/kotaawan/lib/feature/main/home/product/new-product.dart:22:19: Error: Field 'futureProduct' should be initialized because its type 'Future' doesn't allow null.</li>
  <li>'Future' is from 'dart:async'.</li>
  <li>'Product' is from 'package:kotaawan/model/product.dart' ('lib/model/product.dart').
  Future futureProduct;
  ^^^^^^^^^^^^^</li>
  </ul>
  <p>FAILURE: Build failed with an exception.</p>
  <ul>
  <li><p>Where:
  Script 'E:\flutter\packages\flutter_tools\gradle\flutter.gradle' line: 991</p>
  </li>
  <li><p>What went wrong:
  Execution failed for task ':app:compileFlutterBuildDebug'.</p>
  </li>
  </ul>
  <blockquote>
  <p>Process 'command 'E:\flutter\bin\flutter.bat'' finished with non-zero exit value 1</p>
  </blockquote>
  <ul>
  <li><p>Try:
  Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.</p>
  </li>
  <li><p>Get more help at <a href="https://help.gradle.org" rel="nofollow noreferrer">https://help.gradle.org</a></p>
  </li>
  </ul>
  <p>BUILD FAILED in 3m 20s
  Exception: Gradle task assembleDebug failed with exit code 1</p>