// Effect: For each messages in ANCESTOR that is between lower_bound_exclusive (exclusive) and upper_bound_inclusive (inclusive), apply the message to the node.
// Effect: For each messages in ANCESTOR that is between lower_bound_exclusive (exclusive) and upper_bound_inclusive (inclusive), apply the message to the node.
// In ANCESTOR, the relevant messages are all in the buffer for child number CHILDNUM.
// In ANCESTOR, the relevant messages are all in the buffer for child number CHILDNUM.