Hi,

I am trying to use this library and the outlook module to parse msg files. The intention is to read msg files and extract body, attachments and headers in order to store those in a spearate system.

However, due to the way HeadersToIgnoreWhenParsingExternalEmails works, some headers like receive date cannot be read.

Would be possible to make the ignore header list "optional" or configurable? Or is there a way to bypass it but not by forking the whole logic in different classes?

I am also ok to provide a PR if such a feature makes sense.

Congrats for the lib and thank you for your work!