Hi, It seems that there is no Sink base class. Some IO connectors (e.g., KafkaIO and TextIO) provide a getNumShard() API. But it is not generally available for all existing Beam IO connectors and potential custom ones. Although some IO connectors are implemented using ParDo/GBK, it is unclear whether the runner can directly parallelize those transforms (e.g., what if it only writes to a single file). Is there a general way for runners to take advantage of sink parallelism?
Thanks, Shen
