code: @Override
      public boolean addAll(Collection<? extends TimeSeriesCollection> c) {
          try {
              final rh_protoClient client = getRpcClient(OncRpcProtocols.ONCRPC_TCP);
              try {
                  final list_of_timeseries_collection enc_c = encodeTSCCollection(c);
                  return BlockingWrapper.execute(() -> client.addTSData_1(enc_c));
              } finally {
                  client.close();
              }
          } catch (OncRpcException | IOException | InterruptedException | RuntimeException ex) {
              LOG.log(Level.SEVERE, "addAll RPC call failed", ex);
              throw new RuntimeException("RPC call failed", ex);
          }
      }
docs: Add multiple TimeSeriesCollections to the history.