anchor.diff:    void addMIMETypes(Map<String, String> types){
       _extToContentType.addAll(types);
     }
  -  
  +
     /**
      * Serve the file [file] to the [request]. The content of the file will be
      * streamed to the response. If a supported [:Range:] header is received, only
  
positive.code: library static_file_handler;
  
  import 'dart:async';
  
negative.code:     void fileError(e) {
        response.statusCode = HttpStatus.NOT_FOUND;
        response.close();
      }
  
      void pipeToResponse(Stream fileContent, HttpResponse response) {
        fileContent.pipe(response).then((_) => response.close()).catchError(
            //TODO
          () => throw new StateError("Streaming file gone wrong.")
        );
      }
  
      void _sendRange(File file, HttpResponse response, String range, length) {
        // TODO We only support one range, where the standard support several.
        Match matches = new RegExp(r"^bytes=(\d*)\-(\d*)$").firstMatch(range);
  
        // If the range header have the right format, handle it.
        if (matches != null) {
          // Serve sub-range.
  