anchor.diff:  // for details. All rights reserved. Use of this source code is governed by a
   // BSD-style license that can be found in the LICENSE.md file.
   
  -import 'dart:async' show Future;
  +import 'dart:async' show Completer, Future;
   import 'dart:convert' show LineSplitter, utf8;
   import 'dart:io' show File, Platform, Process, exitCode;
   
  
positive.code:       "\n\n");
  
    List<WrappedProcess> startedProcesses = [];
    WrappedProcess? leakTest;
    {
      // Very slow: Leak-test.
  
negative.code:   }
  
    // Wait for everything to finish.
    await startedDelayedProcess.future;
    List<int> exitCodes =
        await Future.wait(startedProcesses.map((e) => e.process.exitCode));
    if (exitCodes.where((e) => e != 0).isNotEmpty) {
  