question: private Map < String , String > produceStream ( String topic ) { List < ProducerRecord < String , String > > messages = new ArrayList < > ( EVENT_CNT ) ; Map < String , String > keyValMap = new HashMap < > ( ) ; for ( int evt = 0 ; evt < EVENT_CNT ; evt ++ ) { long runtime = System . currentTimeMillis ( ) ; String key = topic + "_" + String . valueOf ( evt ) ; String msg = runtime + String . valueOf ( evt ) ; messages . add ( new ProducerRecord < > ( topic , key , msg ) ) ; keyValMap . put ( key , msg ) ; } kafkaBroker . sendMessages ( messages ) ; return keyValMap ; }
target:  Sends messages to Kafka.