Build 3.5.0.98 of xlsgen improves the speed of reading of XLSX files (and their variants, XLSM, XLST, ...).

What we have done in this build is pre-tokenize XML nodes so that the parsing phase is faster for loading the parts of the file which can be arbitrarily big.

This is an ongoing work. We won't be done until reading XLSX files is as fast as reading XLS files (even though there is more work due to the unencoded nature of data and formulas in XLSX files).