compare_stream

# File lib/bundler/vendor/fileutils/lib/fileutils.rb, line 743
  def compare_stream(a, b)
    bsize = fu_stream_blksize(a, b)
    sa = String.new(capacity: bsize)
    sb = String.new(capacity: bsize)
    begin
      a.read(bsize, sa)
      b.read(bsize, sb)
      return true if sa.empty? && sb.empty?
    end while sa == sb
    false
  end