transfer_encoding

# File actionmailer/lib/action_mailer/tmail_compat.rb, line 12
    def transfer_encoding(value = nil)
      if value
        message = 'Message#transfer_encoding is deprecated, ' <<
                  'please call Message#content_transfer_encoding with the same arguments'
        ActiveSupport::Deprecation.warn(message, caller[0,2])
        content_transfer_encoding(value)
      else
        old_transfer_encoding
      end
    end