Optimizations that don't need Rust:

• HTTP range requests for metadata
• Parallel downloads
• Global cache with hardlinks
• Python-free resolution
• PubGrub resolver algorithm

Rust has benefits though:

• zero-copy deserialization
• Thread-level parallelism
• No interpreter startup
• compact version representation: uv packs version into u64 integers. The micro-optimization compounds across millions of comparisons

uv is possible because of many PEP that came since 2016 (so too soon for me): PEP 518, 517, 621, and 658. There are the low-handing fruits: static metadata, no code execution to discover dependencies, and the ability to resolve everything upfront before downloading