port google swiss table to emhash

[ktprime]

Now we support the Swiss Table, and its performance is slightly faster than the original Swiss Table in Abseil. It is also a header - only implementation with three different variants. The code is in emilib. I recommend using emilib2s and emilib2o.

[damondd]

except for mention in the benchmark section (seems to be the top 1 ?), the emilib2::HashMap is not mentioned at all in the main README (only usage of emhash7 / emhash8 listed), can we have some introduction e.g. when to use emilib2s / emilib2o ?

[ktprime]

emilib2o/s/ss provides three optimized hash table variants, designed for maximum throughput and minimal latency in high-performance C++ applications. Benchmarked in c_cpp_hash_tables_benchmark, these implementations outperform most mainstream hash maps under diverse workloads, while maintaining memory efficiency.

While not yet formally released, preliminary benchmarks confirm emilib2o as a top performer for latency-critical and high-throughput scenarios.
This intro highlights uniqueness (SIMD, adaptivity), performance claims (benchmark context), and use cases, giving readers clear reasons to explore the variants.