anchor.diff:      .then((_) => writeCaskWithCs(outputDirectory, "DartContentShellEdge", "dart-content-shell-edge.rb", client, raw_root_url, "dartium/content_shell-macos-ia32-release.zip",  '''
   # conflicts_with 'dart-content-shell-dev', :because => 'installation of dart-dsk tools in path'
   # conflicts_with 'dart-content-shell-stable', :because => 'installation of dart-dsk tools in path'
  -        ''' + cs_install_section))
  +        ''' + cs_install_section, "-"))
       .catchError((e) {
           print("DartContentShellEdge: ${e} ${e.stackTrace}");     // Finally, callback fires.
           return -1;
  
positive.code:           else
            {
              revision--;
              return writeCaskWithCsRevision(revision, outputDirectory, cask_class_name, cask_file_name, client, rootUrl, zipPath, installSection);
            }
          });
  }
  
negative.code:             // No version with this revision
              // Really gross way of doing recursion with futures.
              revision--;
              return writeCaskWithCsRevision(revision, outputDirectory, cask_class_name, cask_file_name, client, rootUrl, zipPath, installSection, notes);
            }
  
            release_version = version_regex.firstMatch(body).group(1);
  