code: public BoxRequestsFolder.AddFolderToCollection getAddToCollectionRequest(String folderId, String collectionId) {
          BoxRequestsFolder.AddFolderToCollection request = new BoxRequestsFolder.AddFolderToCollection(folderId, collectionId, getFolderInfoUrl(folderId), mSession);
          return request;
      }
docs: Gets a request that adds a folder to a collection
  
  @param folderId        id of folder to add to collection
  @param collectionId    id of collection to add the folder to
  @return      request to add a folder to a collection