fix(xep): Do not set C2S counter to 0 after connecting

packages/moxxmpp/lib/src/xeps/xep_0198/xep_0198.dart

@@ -188,7 +188,9 @@ class StreamManagementManager extends XmppManagerBase {
       switch (event.state) {
         case XmppConnectionState.connected:
           // Push out all pending stanzas
-          await onStreamResumed(0);
+          if (!_streamResumed) {
+            await _resendStanzas();
+          }
           break;
         case XmppConnectionState.error:
         case XmppConnectionState.notConnected:
@@ -407,20 +409,23 @@ class StreamManagementManager extends XmppManagerBase {
     return state;
   }
 
+  Future<void> _resendStanzas() async {
+    final stanzas = _unackedStanzas.values.toList();
+    _unackedStanzas.clear();
+
+    for (final stanza in stanzas) {
+      await getAttributes().sendStanza(stanza, awaitable: false);
+    }
+  }
+
   /// To be called when the stream has been resumed
   @visibleForTesting
   Future<void> onStreamResumed(int h) async {
     _streamResumed = true;
     await _handleAckResponse(StreamManagementAckNonza(h));
 
-    final stanzas = _unackedStanzas.values.toList();
-    _unackedStanzas.clear();
-
     // Retransmit the rest of the queue
-    final attrs = getAttributes();
-    for (final stanza in stanzas) {
-      await attrs.sendStanza(stanza, awaitable: false);
-    }
+    await _resendStanzas();
   }
 
   /// Pings the connection open by send an ack request

packages/moxxmpp/test/xeps/xep_0198_test.dart

@@ -733,6 +733,15 @@ void main() {
         "<resume xmlns='urn:xmpp:sm:3' previd='id-1' h='10' />",
         "<resumed xmlns='urn:xmpp:sm:3' h='id-1' h='12' />",
       ),
+      StanzaExpectation(
+        "<iq to='localhost' type='get' from='polynomdivision@test.server/abc123' xmlns='jabber:client' />",
+        '',
+        ignoreId: true,
+      ),
+      StanzaExpectation(
+        "<r xmlns='urn:xmpp:sm:3' />",
+        '',
+      ),
     ]);
 
     final conn = XmppConnection(
@@ -780,7 +789,7 @@ void main() {
 
     // Wait for reconnect
     await Future<void>.delayed(const Duration(seconds: 5));
-    expect(fakeSocket.getState(), 14);
+    expect(fakeSocket.getState(), 12);
   });
 
   test('Test SASL2 inline stream resumption', () async {