Closing sheet does not free memory

[demidafonichev]

Hi,
I am trying to write a file with 200+ sheets of 10k+ rows of data and memory consumption is very high (around 7gb)
I tried stream writing data but it still takes too much ram (~700mb) even if a manually close sheets with sheet.Close() after writing all data which seems to not do anything

I checked if combination of saving file and reopening it for new sheet would help and it did (peak memory consumption was 70mb), but each sheet was writing slower and slower due to re-reading all data from file

Can there be a hybrid solution where I can manually close current sheet and free the memory without closing file?