Gem::Request#fetch

# File tmp/rubies/ruby-3.0.5/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