Improve performance using `Array#sum`

[tricknotes]

The following micro benchmark shows Array#sum is better than Array#map with Array#inject.

require 'benchmark'

array = 4.times.to_a

Benchmark.bm(24) {|x|
  x.report('Array#sum') do
    100000.times {
      array.sum(0, &:itself)
    }
  end

  x.report('Array#map & Array#inject') do
    100000.times {
      array.map(&:itself).inject(0, &:+)
    }
  end
}

$ ruby -v
ruby 3.1.3p185 (2022-11-24 revision 1a6b16756e) [arm64-darwin21]
$ ruby benchmard.rb
                               user     system      total        real
Array#sum                  0.014578   0.000027   0.014605 (  0.014607)
Array#map & Array#inject   0.040410   0.000191   0.040601 (  0.040623)

[yob]

Correct me if I'm wrong, but I believe Array#sum was introduced in ruby 2.4. Puma 5.0 supports ruby 2.2+, and puma 6.0 increases that minimum version to 2.4+.

I'm up for merging this, but would prefer to wait until we depend on puma 6 and can safely assume all users are on ruby 2.4+.

[tricknotes]

Thanks for your reply, @yob. Okay, I missed that puma supports older Ruby versions. I'm keeping this PR as opened.