NTLM support is confusing

[lukebergen]

https://github.com/WinRb/Viewpoint/blob/master/lib/ews/ews_client.rb#L30 says that in order to use NTLM/negotiate, "you do not need to pass this parameter" (said of user and password). However, if I try to run Viewpoint::EWSClient.new(endpoint) I get an error when the code tries to call nil.dup.

Is the heredoc incorrect here or is the code making a bad assumption about user/password always being passed?