code: public void addRequestFilter(String name, RequestFilter requestFilter) {
      if (isRequestFilterAdded(name)) {
        throw new IllegalArgumentException("Duplicate request filter: " + name);
      }
      proxy.addRequestFilter(requestFilter);
      requestFilters.put(name, requestFilter);
    }
docs: Add a custom request filter which allows to track/modify all requests from browser to server
  
  @param name unique name of filter
  @param requestFilter the filter