Also, for what it's worth: I just ran my checksum benchmarker using a freshly built python a la my PR.  Here are my results when hashing 462183782 bytes (dicey-dungeons-linux64.zip):

                                  hash
 algorithm  time        bytes/sec size hash 
 ---------  ---------- ---------- ---- ---------------------------------
    blake3  0.18976406 2435570699   64 0c72d0a07ba767b75b0c99fed38fda...
      sha1  0.21692419 2130623562   40 9fb83614394cd3b39e42b1d9f84a3c...
    sha256  0.26399648 1750719480   64 2320129f2545ff8606d3db1d706d86...
    sha224  0.28097475 1644929957   56 133b5da8d8b387f2bcfd69b0c73ed8...
       md4  0.34185237 1351998195   32 dea7585ea9fa4520687bab1dc671858e
   blake2b  0.53724666  860282275  128 e3653f33858a83b386c2fe865280a1...
       md5  0.58128106  795112407   32 299440e1968cf8f8abc288bac8c0a4fa
sha512_224  0.64589952  715566066   56 413d48b782f114870ef80815540678...
    sha384  0.64645893  714946859   96 b1c1cd96cef79c15f2171b8aa81304...
    sha512  0.65424513  706438241  128 e7d0cec3fe8b73d1534a7bdb484176...
sha512_256  0.68371638  675987586   64 3f58faba70cea4d6ea8a8371e71bbb...
  md5-sha1  0.80361958  575127576   72 299440e1968cf8f8abc288bac8c0a4...
 shake_128  0.84424524  547452041   64 c62a813897b81f67822fc07115deae...
   blake2s  0.85661793  539544839   64 cb8bd19c6ca446bbf7a8abbec61dc5...
  sha3_224  0.95759645  482649850   56 6f96d117c7fcbcd802b222854db644...
 shake_256  1.0152032   455262322   64 2d9f9dafe0ddf792c6407910946845...
  sha3_256  1.015744    455019929   64 cc5d55fe0ac31f6e335da1bc6abaf3...
  sha3_384  1.3235858   349190644   96 13206910ff231fe51a38fe637ded30...
       sm3  1.4478934   319211203   64 021cd913540d95b13a03342b54f80d...
 ripemd160  1.4737549   313609670   40 1a956000b88267ec8fc23327d22548...
  sha3_512  1.9131832   241578418  128 e84b9f499b013956f6f36c93234ca3...

"time" is wall time in seconds.  So, yes, BLAKE3 was the fastest hash algorithm available on my machine--2.4GB/sec!

(I'm a little surprised by that result actually.  My CPU is pretty modern, so I assume it has the SHA1 extensions.  And I further assume we're using OpenSSL, and OpenSSL will use those extensions when available.  If BLAKE3 is *still* faster that OpenSSL, well! hats off to the BLAKE3 team.  And that just goes to show you how useful SIMD extensions are!)