- 
           array $return->headers - 
           an associative array of the headers. The keys of the array
           are the header names (lowercased) whilst the values are the
           header values (original case). If there are multiple headers
           with the same name (eg. Received: ) 
           then the value is a
           numerically indexed array of each of the header values.
           If the parameter decode_headers 
           is specified as TRUE, the headers will be decoded 
           according to RFC 2047.
           
- 
           string $return->ctype_primary - 
           the first part of the content type (ie. before the forward slash).
           Eg. if the content type is 
           multipart/mixed, ctype_primary would
           be "multipart". 
           
- 
           string $return->ctype_secondary - 
           the second part of the content type. Eg. If the content type is
           multipart/mixed, ctype_secondary would 
           be "mixed". 
           
- 
           array $return->ctype_parameters - 
           if the content type header has any parameters 
           (eg. boundary="=_hudfhdsalfhds8fy8329hfj")
           then 
           they will be in this associative array. Keys are the parameter
           name (eg. boundary) whilst the values 
           are the parameter
           values (eg. =_hudfhdsalfhds8fy8329hfj). 
           
- 
           string $return->disposition - 
           if the Content-Disposition header is present, its value
           will be given here. This is usually either
           "inline" or
           "attachment". 
           
- 
           array $return->d_parameters - 
           if any parameters are given with the Content-Disposition header,
           they will be given here in an associative array, keys being the 
           parameter names and values being the parameter values. 
           "name" and "filename"
           are two common examples here. 
           
- 
           array $return->body - 
           if the include_bodies parameter is given 
           when instanciating the class, (either statically or via a
           concrete instance), then this will be present if the part
           in question has a body. 
           MIME parts with content type multipart/*
           generally do not not have bodies, instead consisting of 
           subparts. If the parameter decode_bodies
           is specified as TRUE then the body will 
           be decoded. 
           
- 
          array $return->parts - 
          if a MIME part consists of subparts, then this array will be 
          present consisting of objects with the same properties as 
          described here.