code: public BoxRequestsFile.DownloadRepresentation getDownloadRepresentationRequest(String id, File targetFile, BoxRepresentation representation) {
          return new BoxRequestsFile.DownloadRepresentation(id, targetFile, representation, mSession);
      }
docs: Gets a request to download a representation object for a given file representation
  
  @param id  id of the file to get the representation from
  @param targetFile  file to store the thumbnail
  @param representation  the representation to be downloaded
  @return  request to download the representation