Logstash 基准cli生成异常

如您所知，Elastic发布了用于logstash基准测试的工具，更多详细信息如下：

但它的文档太差了，我总是在Centos 8上遇到异常（我尝试了Java1.8和Java11，但没有任何帮助）

有人可以解释它是如何工作的，我如何修复它

谢谢

[root@lstash logstash]# java -cp '/root/logstash/tools/benchmark-cli/build/libs/benchmark-cli.jar:*' org.logstash.benchmark.cli.Main --testcase=baseline --workdir=/tmp/benchmark2 --distribution-version=7.9.0
Logstash Benchmark
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Benchmarking Version: 7.9.0
Logstash Parameters: -w 2 -b 128
Running Test Case: baseline (x1)
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Using Logstash 7.9.0 from cache.
Start Time: Thu 8 27 14:38:30 2020 EDT
Exception in thread "main" java.lang.IllegalStateException: java.util.concurrent.ExecutionException: java.lang.NullPointerException
        at org.logstash.benchmark.cli.cases.GeneratorToStdout.run(GeneratorToStdout.java:73)
        at org.logstash.benchmark.cli.cases.GeneratorToStdout.run(GeneratorToStdout.java:39)
        at org.logstash.benchmark.cli.Main.execute(Main.java:208)
        at org.logstash.benchmark.cli.Main.main(Main.java:150)
Caused by: java.util.concurrent.ExecutionException: java.lang.NullPointerException
        at java.base/java.util.concurrent.FutureTask.report(FutureTask.java:122)
        at java.base/java.util.concurrent.FutureTask.get(FutureTask.java:205)
        at org.logstash.benchmark.cli.LsMetricsMonitor$MonitorExecution.stopAndGet(LsMetricsMonitor.java:179)
        at org.logstash.benchmark.cli.cases.GeneratorToStdout.run(GeneratorToStdout.java:71)
        ... 3 more
Caused by: java.lang.NullPointerException
        at org.logstash.benchmark.cli.LsMetricsMonitor.readNestedLong(LsMetricsMonitor.java:144)
        at org.logstash.benchmark.cli.LsMetricsMonitor.getCounts(LsMetricsMonitor.java:113)
        at org.logstash.benchmark.cli.LsMetricsMonitor.call(LsMetricsMonitor.java:68)
        at org.logstash.benchmark.cli.LsMetricsMonitor.call(LsMetricsMonitor.java:42)
        at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
        at java.base/java.lang.Thread.run(Thread.java:834)