Performance slowdown 20x between 3.2.0 and master

[ay89607]

Hi! I'm trying to use the library for our project and found that master branch performance is much slower vs. 3.2.0 (just took older version randomly), especially for GZip compression.

I ran both tests on the same machine, master on VS 2019 (Release/Any CPU), 3.2.0 on VS2017 (Release/Any CPU), Ctrl-F5 - just 2 different repos, no code changes.

Here is results from Parquet.Runner for 3.2.0:

0:40:55,972|INF|Parquet.Runner.Program|iteration #0: 00:00:00.2031456, uwp: 00:00:00.0994359, gwt: 00:00:00.1457194 0:40:56,345|INF|Parquet.Runner.Program|iteration #1: 00:00:00.1771764, uwp: 00:00:00.0418373, gwt: 00:00:00.1331094 0:40:56,679|INF|Parquet.Runner.Program|iteration #2: 00:00:00.1514195, uwp: 00:00:00.0423653, gwt: 00:00:00.1344789 0:40:57,012|INF|Parquet.Runner.Program|iteration #3: 00:00:00.1546678, uwp: 00:00:00.0447164, gwt: 00:00:00.1292321 0:40:57,355|INF|Parquet.Runner.Program|iteration #4: 00:00:00.1451514, uwp: 00:00:00.0400017, gwt: 00:00:00.1530406 0:40:57,680|INF|Parquet.Runner.Program|iteration #5: 00:00:00.1384282, uwp: 00:00:00.0567719, gwt: 00:00:00.1253477 0:40:57,980|INF|Parquet.Runner.Program|iteration #6: 00:00:00.1262184, uwp: 00:00:00.0387629, gwt: 00:00:00.1299687 0:40:58,312|INF|Parquet.Runner.Program|iteration #7: 00:00:00.1518486, uwp: 00:00:00.0446676, gwt: 00:00:00.1302474 0:40:58,645|INF|Parquet.Runner.Program|iteration #8: 00:00:00.1448375, uwp: 00:00:00.0510432, gwt: 00:00:00.1321102 0:40:59,002|INF|Parquet.Runner.Program|iteration #9: 00:00:00.1638344, uwp: 00:00:00.0560278, gwt: 00:00:00.1316949 0:40:59,008|INF|Parquet.Runner.Program|mean(read): 00:00:00.1556727, mean(uw): 00:00:00.0515630, mean(gw): 00:00:00.1344949

Here is results from Parquet.Runner for master:

iteration #0: 00:00:00.3910547, uwp: 00:00:00.3726689, gwt: 00:00:02.4269554 iteration #1: 00:00:00.2854977, uwp: 00:00:00.2408480, gwt: 00:00:02.1413147 iteration #2: 00:00:00.2963417, uwp: 00:00:00.2690069, gwt: 00:00:02.3192123 iteration #3: 00:00:00.2569918, uwp: 00:00:00.2376890, gwt: 00:00:02.0613361 iteration #4: 00:00:00.3288451, uwp: 00:00:00.2519022, gwt: 00:00:02.2089186 iteration #5: 00:00:00.2533449, uwp: 00:00:00.2269109, gwt: 00:00:02.0503941 iteration #6: 00:00:00.2645899, uwp: 00:00:00.2278158, gwt: 00:00:02.0869678 iteration #7: 00:00:00.2557560, uwp: 00:00:00.2440898, gwt: 00:00:02.0265803 iteration #8: 00:00:00.2819648, uwp: 00:00:00.2333260, gwt: 00:00:02.1166082 iteration #9: 00:00:00.2821608, uwp: 00:00:00.2289063, gwt: 00:00:02.0486098 mean(read): 00:00:00.2896547, mean(uw): 00:00:00.2533163, mean(gw): 00:00:02.1486897