anchor.diff:  
           // yeah, silly. ctx.fail should blow up. Should not get heer
           assert(dartDocSuccess);
  +
  +        if(postBuild != null) {
  +          // TODO: this should be platfrom specific...pathos?
  +          return postBuild(ctx.getSubLogger('post-build'), dir.path);
  +        }
         });
   }
  
positive.code:       .then((String commitMessage) {
  
          return gitDir.populateBranch(targetBranch,
              (TempDir td) => _doDocsPopulate(ctx, td, libs, packageDir, excludeList, linkApi),
              commitMessage);
        })
        .then((Commit value) {
  
negative.code:  *
   * [delayedLibraryList] a [List<String>] mapping to paths to libraries or some
   * combinations of [Future] or [Function] values that return a [List<String>].
   *
   * [postBuild] A [Function] to call before content is committed. It has the
   * signature `Future postBuild(TaskLogger logger, String tempDocPath)`. Use this
   * if you want to modify the doc output.
   */
  Task createDartDocTask(dynamic delayedLibraryList, {
    String targetBranch: 'gh-pages',
    String packageDir: 'packages/',
    Iterable<String> excludeLibs,
    bool linkApi: false,
    Func2<TaskContext, String, Future> postBuild
    }) {
    requireArgumentNotNull(targetBranch, 'targetBranch');
    requireArgumentNotNull(packageDir, 'packageDir');
  
  