• [API] Add full peer certificate chain API.
• [API, IMPROVEMENT] Make the CRYPTO-frame stash limit configurable (#680).
• [FIX] Check request content-length when DATA ends with an empty FIN.
• [FIX] Release STREAM frames on packet-processing errors.
• [FIX] Avoid 32-bit Cubic arithmetic overflow.
• [IMPROVEMENT] Use 64-bit connection statistics counters.
• [FIX] Sample programs: fix large perf transfers and shutdown cleanup.