def install_binary(name)
    topic "Installing #{name}"
    bin_dir = "bin"
    FileUtils.mkdir_p bin_dir
    Dir.chdir(bin_dir) do |dir|
      if name.match(/^node\-/)
        @node_installer.install
        # need to set PATH here b/c `node-gyp` can change the CWD, but still depends on executing node.
        # the current PATH is relative, but it needs to be absolute for this.
        # doing this here also prevents it from being exported during runtime
        node_bin_path = File.absolute_path(".")
        # this needs to be set after so other binaries in bin/ don't take precedence"
        ENV["PATH"] = "#{ENV["PATH"]}:#{node_bin_path}"
      elsif name.match(/^yarn\-/)
        FileUtils.mkdir_p("../vendor")
        Dir.chdir("../vendor") do |vendor_dir|
          @yarn_installer.install
          yarn_path = File.absolute_path("#{vendor_dir}/#{@yarn_installer.binary_path}")
          ENV["PATH"] = "#{yarn_path}:#{ENV["PATH"]}"
        end
      else
        @fetchers[:buildpack].fetch_untar("#{name}.tgz")
      end
    end
  end
vendors individual binary into the slug
@param [String] name of the binary package from S3.
Example: https://heroku-buildpack-ruby.s3.us-east-1.amazonaws.com/node-0.4.7.tgz, where name is "node-0.4.7"