+ * Each node in a wakeup tree represents a single step
+ * taken in an extension of the execution represented
+ * by the tree within which the node is contained. That is,
+ * a node in the tree is one step on a "pre-defined"
+ * path forward for some execution sequence. The partial
+ * execution that is implicitly represented by the node
+ * is that formed by taking each step on the (unique)
+ * path in the tree from the root node to this node.
+ * Thus, the tree itself contains all of the paths
+ * that "should be" searched, while each node is
+ * simply a step on each path.