function fnv1a64(str) {
	let hash = FNV_OFFSET_64;
	for (let i = 0, len = str.length; i < len; i++) {
		hash ^= BigInt(str.charCodeAt(i));
		hash = BigInt.asUintN(64, hash * FNV_PRIME_64);
	}
	return hash;
}
Computes a 64-bit FNV-1a hash value for the given string.
See https://en.wikipedia.org/wiki/Fowler%E2%80%93Noll%E2%80%93Vo_hash_function
@param {string} str The input string to hash
@returns {bigint} - The computed hash value.