Support parameters for MAIL FROM and RCPT TO
I suggest extending
Net::SMTP#rcpto so they accept an additional optional Array or Hash of parameters.
Net::SMTP#open_message_stream, I suggest that in addition to a String email address (or arrays of Strings), these methods should accept a pair (or arrays of pairs) of
[addr, params], where
addr is the String email address, and
params is an Array or Hash of parameters.
In order for the parameters to be useful, we should expose the capabilities reported by
capable? should be made public.
Pull request: https://github.com/ruby/ruby/pull/3359