In the construction in Fig.6.4, we use a “distributed” implementation of a “head” reference (to the node whose decide Next field it will try to modify) to avoid having to create an object that allows...

In the construction in Fig.6.4, we use a “distributed” implementation of a “head” reference (to the node whose decide Next field it will try to modify) to avoid having to create an object that allows repeated consensus. Replace this implementation with one that has no head reference at all, and finds the next “head” by traversing down the log from the start until it reaches a node with a sequence number of 0 or with the highest nonzero sequence number.