void update(const TaskStatus& status)
  {
    CHECK_EQ(SUBSCRIBED, state);

    LOG(INFO)
      << "Task " << status.task_id().value()
      << " is in state " << TaskState_Name(status.state())
      << (status.has_message() ? " with message: " + status.message() : "");

    if (status.has_uuid()) {
      Call call;
      call.set_type(Call::ACKNOWLEDGE);

      CHECK(framework.has_id());
      call.mutable_framework_id()->CopyFrom(framework.id());

      Call::Acknowledge* acknowledge = call.mutable_acknowledge();
      acknowledge->mutable_agent_id()->CopyFrom(status.agent_id());
      acknowledge->mutable_task_id()->CopyFrom(status.task_id());
      acknowledge->set_uuid(status.uuid());

      mesos->send(call);
    }

    if (status.state() == TaskState::TASK_KILLED ||
        status.state() == TaskState::TASK_LOST ||
        status.state() == TaskState::TASK_FAILED ||
        status.state() == TaskState::TASK_ERROR) {
      ++metrics.abnormal_terminations;
    }
  }