Please return parsed headers also in extract

[KrishnaPG]

Thank you for sharing this work. This is helpful.

Currently, the extract method returns LetterparserMail which holds few fields along with the html/text.

To get all the headers we have to make additional call parse, which the extract method already does internally.

Could you please return the parsed headers also inside the LetterparserMail?

When we need to process the html or text of the parsed mail (or save them as a file onto disk), it is very helpful to have access to all the headers (such as threadId, messageId etc. optional headers, which gives more context to the message).

Kindly consider including the parsed headers as a field into the return value of extract method. Thank you.