Subject: Email with embedded message
From: Sender <[email-masked]>
To: <[email-masked]>
Date: Wed, 15 Jul 2020 19:48:41 +0100

Example outer message.
Example second line.

Subject: Embedded subject line
From: "Embed sender" <[email-masked]>
To: <[email-masked]>
Date: Wed, 15 Jul 2020 12:34:56 +0000

Example embedded message.
Second line.