To: list@example.com
From: user@example.com
Subject: Test Message
Message-ID: <msg@example.com>
Date: Thu, 3 Dec 2020 15:18:27 +0100
MIME-Version: 1.0
Content-Type: multipart/mixed;
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This is a plain text body

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VW0gZnLDvGhlcmUgTmFjaHJpY2h0ZW4K

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