This object supervises the traversal of the data graph and the moving of data from one
DataNodeto its children. The data graph is used to manage data from input devices, etc. See the overview of the data graph in dataNode.h.
Pick up any nodes that didn’t get completely traversed. These must be nodes that have multiple parents, with at least one parent completely outside of the data graph.
Returns the currently-executing thread object, as passed to the