public void tryOpenChannel(int channelIndex) {
    if (!channelOpened[channelIndex]) {
      downStreamChannelList.get(channelIndex).open();
      channelOpened[channelIndex] = true;
    }
  }
max bytes this ShuffleSinkHandle can reserve.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/execution/exchange/sink/ShuffleSinkHandle.java