presto-main/src/main/java/io/prestosql/operator/PipelineContext.java/PipelineContext/getProcessedInputDataSize
class PipelineContext:    public CounterStat getProcessedInputDataSize()
    {
        CounterStat stat = new CounterStat();
        stat.merge(processedInputDataSize);
        for (DriverContext driver : drivers) {
            stat.merge(driver.getInputDataSize());
        }
        return stat;
    }