Fix configuration of threads in environment

benchmarks/workload-generator-commons/src/main/java/theodolite/commons/workloadgeneration/LoadGenerator.java

@@ -14,6 +14,7 @@ public final class LoadGenerator {
   private static final int NUMBER_OF_KEYS_DEFAULT = 10;
   private static final int PERIOD_MS_DEFAULT = 1000;
   private static final int VALUE_DEFAULT = 10;
+  private static final int THREADS_DEFAULT = 4;
   private static final String SCHEMA_REGISTRY_URL_DEFAULT = "http://localhost:8081";
   private static final String KAFKA_TOPIC_DEFAULT = "input";
   private static final String KAFKA_BOOTSTRAP_SERVERS_DEFAULT = "localhost:9092"; // NOPMD
@@ -113,6 +114,9 @@ public final class LoadGenerator {
     final double value = Double.parseDouble(Objects.requireNonNullElse(
         System.getenv(ConfigurationKeys.VALUE),
         Integer.toString(VALUE_DEFAULT)));
+    final int threads = Integer.parseInt(Objects.requireNonNullElse(
+        System.getenv(ConfigurationKeys.THREADS),
+        Integer.toString(THREADS_DEFAULT)));
     final String kafkaBootstrapServers = Objects.requireNonNullElse(
         System.getenv(ConfigurationKeys.KAFKA_BOOTSTRAP_SERVERS),
         KAFKA_BOOTSTRAP_SERVERS_DEFAULT);
@@ -146,7 +150,8 @@ public final class LoadGenerator {
                     kafkaInputTopic,
                     schemaRegistryUrl,
                     kafkaProperties)
-                .forConstantValue(value)));
+                .forConstantValue(value))
+                    .setThreads(threads));
   }
 
 }