presto-client/src/main/java/io/prestosql/client/StageStats.java/StageStats/toString
class StageStats:    @Override
    public String toString()
    {
        return toStringHelper(this)
                .add("state", state)
                .add("done", done)
                .add("nodes", nodes)
                .add("totalSplits", totalSplits)
                .add("queuedSplits", queuedSplits)
                .add("runningSplits", runningSplits)
                .add("completedSplits", completedSplits)
                .add("cpuTimeMillis", cpuTimeMillis)
                .add("wallTimeMillis", wallTimeMillis)
                .add("processedRows", processedRows)
                .add("processedBytes", processedBytes)
                .add("subStages", subStages)
                .toString();
    }