in flink-connector-cassandra/src/main/java/org/apache/flink/streaming/connectors/cassandra/CassandraSink.java [147:154]
public CassandraSink<IN> setParallelism(int parallelism) {
if (useDataStreamSink) {
sink1.setParallelism(parallelism);
} else {
sink2.setParallelism(parallelism);
}
return this;
}