(PersistentProtocolBufferMap)fromProtoValue(field, iterator.next());
Object k = v.valAt(map_field_by);
PersistentProtocolBufferMap existing = (PersistentProtocolBufferMap)map.valAt(k);
map = map.assoc(k, def.mapValue(field, existing, v));
}
return map.persistent();
} else if (options.getExtension(Extensions.counter)) {
Object count = iterator.next();
while (iterator.hasNext()) {
count = Numbers.add(count, iterator.next());
}