Declaration Syntax RemarksWhen doing ZLIB or Deflate compression, the library fills a buffer, then passes it to the compressor for compression. Then the library reads out the compressed bytes. This happens repeatedly until there is no more uncompressed data to compress. This property sets the size of the buffer that will be used for chunk-wise compression. In order for the setting to take effect, your application needs to set this property before calling one of the ZipFile.Save() overloads.
Setting this affects the performance and memory efficiency of compression and decompression. For larger files, setting this to a larger size may improve compression performance, but the exact numbers vary depending on available memory, the size of the streams you are compressing, and a bunch of other variables. I don't have good firm recommendations on how to set it. You'll have to test it yourself. Or just leave it alone and accept the default.