anchor.diff:     * Create a new [HttpBodyHandler] to be used with a [Stream]<[HttpRequest]>,
      * e.g. a [HttpServer].
      *
  -   * If the page was served using different encoding than UTF-8, set
  +   * If the page is served using different encoding than UTF-8, set
      * [defaultEncoding] accordingly. This is required for parsing
  -   * 'application/x-www-form-urlencoded' content correctly.
  +   * `multipart/form-data` content correctly. See the class comment
  +   * for more information on `multipart/form-data`.
      */
     HttpBodyHandler({Encoding defaultEncoding: Encoding.UTF_8})
         : _transformer = new _HttpBodyHandlerTransformer(defaultEncoding);
  
positive.code:  *           ...
   *         });
   *
   * The following mime-types will be handled specially:
   *   - text/\*
   *   - application/json
   *
   * All other mime-types will be returned as [List<int>].
   */
  class HttpBodyHandler
      implements StreamTransformer<HttpRequest, HttpRequestBody> {
  
negative.code: 
  
  /**
   * [HttpBodyHandler] is a helper class for processing and collecting
   * HTTP message data in an easy-to-use [HttpBody] object. The content
   * body is parsed, depending on the `Content-Type` header field. When
   * the full body is read and parsed the body content is made
   * available. The class can be used to process both server requests
   * and client responses.
   *
   * The following content types are recognized:
   *
   *     text/\*
   *     application/json
   *     application/x-www-form-urlencoded
   *     multipart/form-data
   *
   *  For content type `text/\*` the body is decoded into a string. The
   *  'charset' parameter of the content type specifies the encoding
   *  used for decoding. If no 'charset' is present the default encoding
   *  of ISO-8859-1 is used.
   *
   *  For content type `application/json` the body is decoded into a
   *  string which is then parsed as JSON. The resulting body is a
   *  [Map].  The 'charset' parameter of the content type specifies the
   *  encoding used for decoding. If no 'charset' is present the default
   *  encoding of UTF-8 is used.
   *
   *  For content type `application/x-www-form-urlencoded` the body is a
   *  query string which is then split according to the rules for
   *  splitting a query string. The resulting body is a `Map<String,
   *  String>`.  If the same name is present several times in the query
   *  string, then the last value seen for this name will be in the
   *  resulting map. The encoding US-ASCII is always used for decoding
   *  the body.
   *
   *  For content type `multipart/form-data` the body is parsed into
   *  it's different fields. The resulting body is a `Map<String,
   *  dynamic>`, where the value is a [String] for normal fields and a
   *  [HttpBodyFileUpload] instance for file upload fields. If the same
   *  name is present several times, then the last value seen for this
   *  name will be in the resulting map.
   *
   *  When using content type `multipart/form-data` the encoding of
   *  fields with [String] values is determined by the browser sending
   *  the HTTP request with the form data. The encoding is specified
   *  either by the attribute `accept-charset` on the HTML form, or by
   *  the content type of the web page containing the form. If the HTML
   *  form has an `accept-charset` attribute the browser will use the
   *  encoding specified there. If the HTML form has no `accept-charset`
   *  attribute the browser determines the encoding from the content
   *  type of the web page containing the form. Using a content type of
   *  `text/html; charset=utf-8` for the page and setting
   *  `accept-charset` on the HTML form to `utf-8` is recommended as the
   *  default for [HttpBodyHandler] is UTF-8. It is important to get
   *  these encoding values right, as the actual `multipart/form-data`
   *  HTTP request sent by the browser does _not_ contain any
   *  information on the encoding. If something else than UTF-8 is used
   *  `defaultEncoding` needs to be set in the [HttpBodyHandler]
   *  constructor and calls to [processRequest] and [processResponse].
   *
   *  For all other content types the body will be treated as
   *  uninterpreted binary data. The resulting body will be of type
   *  `List<int>`.
   *
   * To use with the [HttpServer] for request messages, [HttpBodyHandler] can be
   * used as either a [StreamTransformer] or as a per-request handler (see
  