code: public <T, E> BatchRequest queue(HttpRequest httpRequest, Class<T> dataClass, Class<E> errorClass,
        BatchCallback<T, E> callback) throws IOException {
      Preconditions.checkNotNull(httpRequest);
      // TODO(rmistry): Add BatchUnparsedCallback with onResponse(InputStream content, HttpHeaders).
      Preconditions.checkNotNull(callback);
      Preconditions.checkNotNull(dataClass);
      Preconditions.checkNotNull(errorClass);
  
      requestInfos.add(new RequestInfo<T, E>(callback, dataClass, errorClass, httpRequest));
      return this;
    }
docs: Queues the specified {@link HttpRequest} for batched execution. Batched requests are executed
  when {@link #execute()} is called.
  
  @param <T> destination class type
  @param <E> error class type
  @param httpRequest HTTP Request
  @param dataClass Data class the response will be parsed into or {@code Void.class} to ignore
  the content
  @param errorClass Data class the unsuccessful response will be parsed into or
  {@code Void.class} to ignore the content
  @param callback Batch Callback
  @return this Batch request
  @throws IOException If building the HTTP Request fails