Gem::Request#fetch

# File tmp/rubies/ruby-3.1.3/lib/rubygems/request.rb, line 135
def fetch
  request = @request_class.new @uri.request_uri

  unless @uri.nil? || @uri.user.nil? || @uri.user.empty?
    request.basic_auth Gem::UriFormatter.new(@uri.user).unescape,
                       Gem::UriFormatter.new(@uri.password).unescape
  end

  request.add_field "User-Agent", @user_agent
  request.add_field "Connection", "keep-alive"
  request.add_field "Keep-Alive", "30"

  if @last_modified
    require "time"
    request.add_field "If-Modified-Since", @last_modified.httpdate
  end

  yield request if block_given?

  perform_request request
end