Zstandardzstd, short for Zstandard, is a fast lossless compression algorithm, targeting real-time compression scenarios at zlib-level and better compression ratios. The zstd compression library provides in-memory compression and decompression functions. The library supports compression levels from 1 up to max_compression_level () (currently 22). Levels >= 20, labeled `--ultra`, should be used with caution, as they require more memory.