Method corrections

src/slave/qos_controllers/load.cpp:67–70

      loadThreshold15Min(_loadThreshold15Min) {}

  Future<list<QoSCorrection>> corrections()
  {
    return usage().then(defer(self(), &Self::_corrections, lambda::_1));
  }

  Future<list<QoSCorrection>> _corrections(const ResourceUsage& usage)
  {