From: Fake Sender <fake_sender@example.invalid>
To: Fake Receiver <fake_receiver@localhost>
Date: Sun, 21 Jun 2020 06:25:49 -0000
Subject: Attachments with charset
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="===============2385509127900810307=="

--===============2385509127900810307==
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit

This is the body.

--===============2385509127900810307==
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
MIME-Version: 1.0
Content-Disposition: attachment; filename="ascii.txt"

This is ASCII

--===============2385509127900810307==
Content-Type: text/plain; charset="koi8-r"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
Content-Disposition: attachment; filename="cyrillic.txt"

=F0=D2=C9=D7=C5=D4

--===============2385509127900810307==
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: base64
MIME-Version: 1.0
Content-Disposition: attachment; filename="emoji.txt"

8J+Yggo=

--===============2385509127900810307==
Content-Type: text/plain
Content-Transfer-Encoding: quoted-printable
Content-Disposition: attachment; filename="bad.txt"
MIME-Version: 1.0

Embedded=F0garbage
--===============2385509127900810307==--