Package check result: NOTE

Check: examples, Result: NOTE
  Examples with CPU (user + system) or elapsed time > 5s
                  user system elapsed
  explain_xgboost 7.31  0.056    1.35
  Examples with CPU time > 2.5 times elapsed time
                  user system elapsed ratio
  explain_xgboost 7.31  0.056    1.35 5.456

No changes to worse in reverse depends.