zstd library changes

zstd library changes

Verified from my end. It's working as expected.

assigned to @ajitj

only one little difference we have tested with zstd.WithEncoderLevel(zstd.SpeedBetterCompression) at line 19 as encoder, _ = zstd.NewWriter(nil, zstd.WithEncoderLevel(zstd.SpeedBetterCompression))

merged

mentioned in commit bf999b40