A try to make rubys Array.uniq faster

hash_uniq.rb

require 'digest'
require 'benchmark'

list = (1..100000).to_a.map(&:to_s).map {|e| Digest::SHA256.hexdigest(e)}
list += list
list.shuffle

def hash_uniq(a)
  a_hash = {}
  a.each do |v|
    a_hash[v] = nil
  end
  a_hash.keys
end

Benchmark.bm do |x|
  x.report(:uniq) { 100.times { list.uniq} }
  x.report(:hash_uniq) { 100.times { hash_uniq(list) } }
end

puts "Results are the same" if list.uniq == hash_uniq(list)

#           user     system      total        real
# uniq      23.750000   0.040000  23.790000 ( 23.823770)
# hash_uniq 18.560000   0.020000  18.580000 ( 18.591803)
# Results are the same