Net::HTTP#sspi_auth?

# File tmp/rubies/ruby-3.0.5/lib/net/http.rb, line 1643
def sspi_auth?(res)
  return false unless @sspi_enabled
  if res.kind_of?(HTTPProxyAuthenticationRequired) and
      proxy? and res["Proxy-Authenticate"].include?("Negotiate")
    begin
      require 'win32/sspi'
      true
    rescue LoadError
      false
    end
  else
    false
  end
end