mail::Header::mime — A structured MIME header.
        #include <libmail/headers.H>
        
        mail::Header::mime content_type("Content-Type", "text/plain");
        
            content_type.parameters.set_simple("charset", "iso-8859-1");
        
        mail::Header::mime content_disposition("Content-Disposition", "attachment")
                                      ("filename", "document.doc")
                                      ("name", "Monthly Sales", "iso-8859-1", "EN");
        
        std::cout << content_type.toString();
        
This class creates a structured MIME header. A structured
      MIME header, like Content-Type
      or Content-Disposition contains
      a literal value, and zero or more “name=setting” parameters,
      separated by semicolons.
Two arguments are provided to the constructor, the
      header's name, and its literal value. After constructing, use
      the parameters
      member to set the parameters. This member has the following
      methods:
Set parameter name to
            value. value must contain US-ASCII text only.
Set parameter name to
            value. charset specifies value's character set. language is optional, and specifies
            value's language.
            value is converted to
            US-ASCII text according to
            RFC 2231.
Remove parameter name.
The toString() returns the
      header as a single text string: “name: value”.
      Long headers are folded accordingly.
Parameters can also be dynamically populated by repeatedly calling the “()”.
One version of the “()”
        operator receives the parameter name and value, and
        corresponds to the set_simple
        method. The second version also receives the character set
        and language information, and corresponds to the
        set function.