code: public synchronized PathHandler addPrefixPath(final String path, final HttpHandler handler) {
          Handlers.handlerNotNull(handler);
          pathMatcher.addPrefixPath(path, handler);
          return this;
      }
docs: Adds a path prefix and a handler for that path. If the path does not start
  with a / then one will be prepended.
  <p>
  The match is done on a prefix bases, so registering /foo will also match /foo/bar.
  Though exact path matches are taken into account before prefix path matches. So
  if an exact path match exists it's  handler will be triggered.
  <p>
  If / is specified as the path then it will replace the default handler.
  
  @param path    If the request contains this prefix, run handler.
  @param handler The handler which is activated upon match.
  @return The resulting PathHandler after this path has been added to it.