public void fill(TezCounters tezCounters) {
    for (Map.Entry<String, LlapFileSystemStatisticsData> threadLocalStats :
        schemeToThreadLocalStats.entrySet()){
      String scheme = threadLocalStats.getKey();
      LlapFileSystemStatisticsData stats = threadLocalStats.getValue();
      tezCounters.findCounter(scheme, FileSystemCounter.BYTES_READ).increment(stats.bytesRead);
      tezCounters.findCounter(scheme, FileSystemCounter.BYTES_WRITTEN).increment(stats.bytesWritten);
      tezCounters.findCounter(scheme, FileSystemCounter.READ_OPS).increment(stats.readOps);
      tezCounters.findCounter(scheme, FileSystemCounter.LARGE_READ_OPS).increment(stats.largeReadOps);
      tezCounters.findCounter(scheme, FileSystemCounter.WRITE_OPS).increment(stats.writeOps);
    }

    if (cpuTime >= 0 && userTime >= 0) {
      tezCounters.findCounter(LlapThreadLocalStatistics.LlapExecutorCounters.EXECUTOR_CPU_NS).increment(cpuTime);
      tezCounters.findCounter(LlapThreadLocalStatistics.LlapExecutorCounters.EXECUTOR_USER_NS).increment(userTime);
    }
  }
Merges the list to a map.
Input list:
1. FileSystem.Statistics (scheme: file)
2. FileSystem.Statistics (scheme: hdfs)
3. FileSystem.Statistics (scheme: hdfs)
Output map:
file : LlapThreadLocalStatistics.StatisticsData (1)
hdfs : LlapThreadLocalStatistics.StatisticsData (2 + 3)
llap-common/src/java/org/apache/hadoop/hive/llap/LlapThreadLocalStatistics.java