presto-main/src/main/java/io/prestosql/execution/SqlTaskExecution.java/SqlTaskExecution/toString
class SqlTaskExecution:    @Override
    public String toString()
    {
        return toStringHelper(this)
                .add("taskId", taskId)
                .add("remainingDrivers", status.getRemainingDriver())
                .add("unpartitionedSources", unpartitionedSources)
                .toString();
    }