anchor.diff:  // Use of this source code is governed by a BSD-style license that can be
   // found in the LICENSE file.
   
  -// @dart=2.9
  +// ignore_for_file: import_of_legacy_library_into_null_safe
   
   import 'dart:async';
   import 'dart:convert';
  
positive.code:   final SseClient sseClient;
  
    int _nextRequestId = 0;
    Notification _lastNotification;
  
    final Map<String, Completer> _completers = {};
  
  
negative.code:     _lastNotification?.close();
    }
  
    Future<T> _callMethod<T>(String method, [Map<String, dynamic>? params]) {
      final id = '${_nextRequestId++}';
      final json = jsonEncode({
        'jsonrpc': '2.0',
  