ruby – 为什么map {} .compact比each_with_object([])更快？

require 'benchmark'

words = File.open('/usr/share/dict/words','r') do |file|
  file.each_line.take(1_000_000).map(&:chomp)
end

Benchmark.bmbm(20) do |x|
  GC.start
  x.report(:map) do
    words.map do |word|
      word.size if word.size > 5
    end.compact
  end

  GC.start
  x.report(:each_with_object) do
    words.each_with_object([]) do |word,long_sizes|
      long_sizes << word.size if word.size > 5
    end
  end
end

输出(ruby 2.3.0)：

Rehearsal --------------------------------------------------------
map                    0.020000   0.000000   0.020000 (  0.016906)
each_with_object       0.020000   0.000000   0.020000 (  0.024695)
----------------------------------------------- total: 0.040000sec

                           user     system      total        real
map                    0.010000   0.000000   0.010000 (  0.015004)
each_with_object       0.020000   0.000000   0.020000 (  0.024183)

我无法理解它,因为我认为each_with_object应该更快：它只需要1个循环和1个新对象来创建一个新数组,而不是2个循环和2个新对象,以防我们组合map和compact.
有任何想法吗？