code: public void addConnection(NFBuildGraphNode fromNode, NFPropertySpec propertySpec, int connectionModelIndex, NFBuildGraphNode toNode) {
          fromNode.addConnection(connectionModelIndex, propertySpec, toNode.getOrdinal());
          toNode.incrementNumIncomingConnections();
      }
docs: Add a connection to this graph.  This method is exposed for efficiency purposes.  It is more efficient than
  {@code addConnection(String connectionModel, String nodeType, int fromOrdinal, String viaPropertyName, int toOrdinal)}
  as it avoids multiple lookups for <code>fromNode</code>, <code>propertySpec</code>, <code>connectionModelIndex</code>
  and <code>toNode</code>.