code: public void processEmployee(WriteBatcher wb, Employee employee) {
      String uri = "/employees/" + employee.getEmployeeId() + ".json";
      try {
        // queue this uri to see if it's in the server and unchanged
        uriQueue.put(uri);
      } catch (InterruptedException e) {
        throw new RuntimeException(e);
      };
      // queue this employee to generate a local hashcode to compare against the
      // server and write this employee to the target if needed
      sourceEmployees.put(uri, employee);
    }
docs: for each Employee record retrieved from the source