Before creating new Spreadsheet::ParseExcel::Stream:
             total       used       free     shared    buffers     cached
Mem:          3011       1250       1761          0          2        177
-/+ buffers/cache:       1071       1940
Swap:          956        177        779
After creating new Spreadsheet::ParseExcel::Stream:
             total       used       free     shared    buffers     cached
Mem:          3011       2257        753          0          2        177
-/+ buffers/cache:       2077        933
Swap:          956        177        779