presto-main/src/main/java/io/prestosql/execution/executor/TaskExecutor.java/TaskExecutor/getRunAwaySplitCount
class TaskExecutor:    @Managed
    public long getRunAwaySplitCount()
    {
        int count = 0;
        for (RunningSplitInfo splitInfo : runningSplitInfos) {
            Duration duration = Duration.succinctNanos(ticker.read() - splitInfo.getStartTime());
            if (duration.compareTo(LONG_SPLIT_WARNING_THRESHOLD) > 0) {
                count++;
            }
        }
        return count;
    }