private void report(final String op, final long cost) {
        System.out.println("Test " + op + ":");
        System.out.println("  Log number   :" + this.totalLogs);
        System.out.println("  Log Size     :" + this.logSize);
        System.out.println("  Batch Size   :" + this.batchSize);
        System.out.println("  Cost time(s) :" + cost / 1000);
        System.out.println("  Total size   :" + (long) this.totalLogs * this.logSize);
    }
benchmark result:
total data : 8G
batchSize:200
1.Test write:
 *   Log number   :524288
 *   Log Size     :16384
 *   Batch Size   :200
 *   Cost time(s) :40s
 *   Total size   :8589934592


2.Test read:
  Log number   :524288
  Log Size     :16384
  Batch Size   :200
  Cost time(s) :6s
  Total size   :8589934592

If batchSize = 500
write cost times = 38s

If batchSize = 1000
write cost times = 32s

@author hzh (642256541@qq.com)
jraft-extension/java-log-storage-impl/src/test/java/com/alipay/sofa/jraft/storage/Benchmark/DefaultLogStorageBenchmark.java