EventReco::Edge Node1 EventReco::Edge   + Edge() + Edge() + getFeatures() + getIndices() Node2 std::vector< float > + elements + elements   Node2->Node1 -m_edgeFeatures Node3 std::pair< int64_t, int64_t > + first_type + second_type + first_type + second_type   Node3->Node1 -m_edgeIndex