If they just used the default, that's SipHash which is optimized for security and DOS resistance, not performance. XXh3 is ~10x faster than that and there's som

If they just used the default, that's SipHash which is optimized for security and DOS resistance, not performance. XXh3 is ~10x faster than that and there's some newer ones that are even faster than Xxh3 like GxHash (like another ~1.5x-2x faster). You would precompute the hash for the constant string list & then compute the hash only for for the set of strings that begin with C/c since "cf-" is a common prefix for those internal headers if I recall correctly, using RawTable to find entries by hash & then comparing against the precomputed value to see if a collision matched before checking a string for equality.