Subject: � 丸数字テスト
From: John Smith <[email-masked]>
To: "[email-masked]" <[email-masked]>
Date: Mon, 27 Aug 2018 09:30:00 +0900

The subject contains a "CIRCLED DIGIT ONE" character (U+2460).
It is undefined in ISO-2022-JP but defined in some vendor-extended
variants such as ISO-2022-JP-MS.