Hmm this is a bit of a pain to refactor without adding lots of extra methods unless I do it like:

```
124   def to_s(form_data = false)
125     msg = self.to_form_data
126     msg << self.content_to_s
127 
128     self.parts.each do |part|
129       msg << "--" + self.bound 
130       msg << "\r\n" unless form_data
131       msg << part.to_s
132     end
133     
134     if self.parts.length > 0
135       msg << "--" + self.bound + "--\r\n"
136     end
137     
138     unless form_data
139       # Force CRLF for SMTP compatibility
140       msg.gsub("\r", '').gsub("\n", "\r\n")
141     end
142   end
```