If desired, the protocol can be optimized to reduce the
number of rejected AppendEntries RPCs. For example,
when rejecting an AppendEntries request, the follower
can include the term of the conflicting entry and the first
index it stores for that term. With this information, the
leader can decrement nextIndex to bypass all of the con-
flicting entries in that term; one AppendEntries RPC will
be required for each term with conflicting entries, rather
than one RPC per entry. In practice, we doubt this opti-
mization is necessary, since failures happen infrequently
and it is unlikely that there will be many inconsistent en-
tries.