// fetch and add time spent in this node
Object[] treePath = treeModel.getPathToRoot((TreeNode) node);
PropertyKey key = treeModel.getPropKey(useProps, treePath);
if (key != null) {
String pathPrefix = key.path();
// For efficiency, we only search through the portion of the
// SortedMap which could contain paths matching our prefix.
// "Matching our prefix" means that it exactly equals our
// prefix, or it begins with our prefix followed by a slash.
// The character after the slash character is the zero '0'.