Gem::LocalRemoteOptions#add_proxy_option

# File tmp/rubies/ruby-3.2.0/lib/rubygems/local_remote_options.rb, line 89
def add_proxy_option
  accept_uri_http

  add_option(:"Local/Remote", "-p", "--[no-]http-proxy [URL]", URI::HTTP,
             "Use HTTP proxy for remote operations") do |value, options|
    options[:http_proxy] = (value == false) ? :no_proxy : value
    Gem.configuration[:http_proxy] = options[:http_proxy]
  end
end