split a content type in its different parts - maybe that could get a more generic name and code as many fields use this format
split a header field like content type in its different parts
split a message in header and body part, if no header or an invalid header is found $headers is empty
decodes a mime encoded String and returns a struct of parts with header and body
explode mime multipart string into seperate parts the parts consist of the header and the body of the mime part.