The api for the HighwaterMarkCheckpoint is: def write(highwaterMarksPerPartition: Map[TopicAndPartition, Long])
def read(topic: String, partition: Int): Long Pretty weird, no? The write method writes a map of all values, obliterating previous values. The read method internally reads back that whole map, then throws away all the values but one and returns that one. It seems like the natural way to do it would be to either read and write one key/value pair or read and write them all together. Is there a rationale for this? Can we change it? It would be nice to reuse this class to track log flushes, and the cleaner point. However in its current form it isn't particularly useful. -Jay
