Internal API change

now query & mutation share same base class
queries are now self-refetchable
queryJobs & mutationJobs now support dynamic key allowing dynamic Query/Mutation creation
query status & mutation status are now just on point & accurate

packages/fl_query/lib/models/mutation_job.dart

@@ -1,17 +1,43 @@
 import 'package:fl_query/mutation.dart';
 
 class MutationJob<T extends Object, V> {
-  final String mutationKey;
+  String _mutationKey;
   MutationTaskFunction<T, V> task;
   final int? retries;
   final Duration? retryDelay;
   final Duration? cacheTime;
 
   MutationJob({
-    required this.mutationKey,
+    required String mutationKey,
     required this.task,
     this.retries,
     this.retryDelay,
     this.cacheTime,
-  });
+  }) : _mutationKey = mutationKey;
+
+  String get mutationKey => _mutationKey;
+
+  static MutationJob<T, V> Function(String queryKey)
+      withVariableKey<T extends Object, V>({
+    required MutationTaskFunction<T, V> task,
+
+    /// a extra key joined with mutationKey by a '#'
+    ///
+    /// useful for matching a group mutation
+    String? preMutationKey,
+    int? retries,
+    Duration? retryDelay,
+    Duration? cacheTime,
+  }) {
+    return (String mutationKey) {
+      if (preMutationKey != null) mutationKey = "$preMutationKey#$mutationKey";
+      return MutationJob<T, V>(
+        mutationKey: mutationKey,
+        task: task,
+        retries: retries,
+        retryDelay: retryDelay,
+        cacheTime: cacheTime,
+      );
+    };
+  }
 }