code: public String save(SaveOptions opts) throws PiliException {
          String path = baseUrl + "/saveas";
          String json = gson.toJson(opts);
  
          try {
              String resp = cli.callWithJson(path, json);
              SaveRet ret = gson.fromJson(resp, SaveRet.class);
              return ret.fname;
          } catch (PiliException e) {
              throw e;
          } catch (Exception e) {
              throw new PiliException(e);
          }
      }
docs: save playback with more options
  
  @param opts
  @return
  @throws PiliException