fix: Wait for the executor.dispose done before exit the isolate (#93)

We send a `null` to the sub isolate the clean up the native
resources(`destroyNativeApiEngine`...), but we do not wait for the
clean-up logic to be finished, which will cause an error if we want to
clean up something relative to the native resources right after the
`dispose` function in sychronize way.

lib/src/platform/io/iris_method_channel_internal_io.dart

@@ -49,7 +49,9 @@ class _Messenger implements DisposableObject {
     }
     _isDisposed = true;
     requestPort.send(null);
-    await responseQueue.cancel();
+    // Wait for `executor.dispose` done in isolate.
+    await responseQueue.next;
+    responseQueue.cancel();
   }
 }
 
@@ -450,8 +452,9 @@ class IrisMethodChannelInternalIO implements IrisMethodChannelInternal {
     // Wait for messages from the main isolate.
     await for (final request in apiCallPort) {
       if (request == null) {
-        // Exit if the main isolate sends a null message, indicating there are no
-        // more files to read and parse.
+        executor.dispose();
+        mainApiCallSendPort.send(null);
+        // Ready exit the isolate.
         break;
       }
 
@@ -494,7 +497,6 @@ class IrisMethodChannelInternalIO implements IrisMethodChannelInternal {
       }
     }
 
-    executor.dispose();
     Isolate.exit(onExitSendPort, 0);
   }
 

test/iris_method_channel_test.dart

@@ -209,8 +209,6 @@ void main() {
   test('disposed', () async {
     await irisMethodChannel.initilize([]);
     await irisMethodChannel.dispose();
-    // Wait for `dispose` completed.
-    await Future.delayed(const Duration(milliseconds: 500));
     final callRecord1 = messenger.callApiRecords
         .where((e) => e.methodCall.funcName == 'destroyNativeApiEngine');
     expect(callRecord1.length, 1);
@@ -227,8 +225,6 @@ void main() {
     await irisMethodChannel.initilize([]);
     await irisMethodChannel.dispose();
     await irisMethodChannel.dispose();
-    // Wait for `dispose` completed.
-    await Future.delayed(const Duration(milliseconds: 500));
     final callRecord1 = messenger.callApiRecords
         .where((e) => e.methodCall.funcName == 'destroyNativeApiEngine');
     expect(callRecord1.length, 1);