query reusability by QueryJob

QueryJob.task External Data Support
Query task is now pure function
Query.data is non-nullable (even the type)

packages/example/lib/query_with_external_data.dart

@@ -0,0 +1,39 @@
+import 'dart:math';
+
+import 'package:fl_query/fl_query.dart';
+import 'package:flutter/material.dart';
+
+final jobWithExternalData = QueryJob<String, String>(
+    queryKey: "external_data",
+    task: (queryKey, data) {
+      return Future.delayed(const Duration(milliseconds: 500),
+          () => "Hello from $queryKey with $data");
+    });
+
+class QueryWithExternalData extends StatelessWidget {
+  const QueryWithExternalData({Key? key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(),
+      body: QueryBuilder<String, String>(
+        job: jobWithExternalData,
+        externalData: (Random().nextDouble() * 200).toString(),
+        builder: (context, query) {
+          if (query.isLoading || query.isLoading || query.data == null) {
+            return const CircularProgressIndicator();
+          }
+          return Container(
+            width: double.parse(query.externalData),
+            height: double.parse(query.externalData),
+            decoration: const BoxDecoration(
+              shape: BoxShape.circle,
+              color: Colors.blue,
+            ),
+          );
+        },
+      ),
+    );
+  }
+}