stop pinger when connection close

bin/surrealdb.dart

@@ -6,33 +6,13 @@ void main(List<String> args) async {
 
   client.connect();
   await client.wait();
-  await client.use('test', 'test');
+  await client.use('ns', 'db');
   await client.signin('root', 'root');
 
-  await client.create('person', TestModel(false, 'title'));
+  final delete = await client.query('DELETE user:5');
 
-  var person = await client.create('person', {
-    'title': 'Founder & CEO',
-    'name': {
-      'first': 'Tobie',
-      'last': 'Morgan Hitchcock',
-    },
-    'marketing': false,
-  });
-  print(person);
-
-  List<Map<String, Object?>> persons = await client.select('person');
-
-  final groupBy = await client.query(
-    'SELECT marketing, count() FROM type::table(\$tb) GROUP BY marketing',
-    {
-      'tb': 'person',
-    },
-  );
-
-  print(groupBy);
-
-  print(persons.length);
+  print(delete);
+  client.close();
 }
 
 class AMODEL {

lib/src/surrealdb.dart

@@ -22,6 +22,8 @@ class SurrealDB {
 
   /// Closes the persistent connection to the database.
   void close() {
+    _pinger?.stop();
+    _pinger = null;
     _wsService.disconnect();
   }
 

lib/src/ws.dart

@@ -102,7 +102,7 @@ class WSService {
     final ws = _ws;
 
     if (ws == null) {
-      return (completer..completeError('ws not connected')).future;
+      return (completer..completeError('websocket not connected')).future;
     }
 
     var id = getNextId();