Date property is not initialized correctly when passed as Header in MimeMessage constructor

[VikKol]

When passing 'Date' header in MimeMessage constructor, Date property is not initialized correctly.
DateTimeOffset.UtcNow is used instead of the header value.

Code example:

var dateTimeString = "Thu, 29 Sep 2022 09:52:47 +0000";
var message = new MimeMessage(new Header(HeaderId.Date, dateTimeString));
message.Date == DateTimeOffset.Parse(dateTimeString); // returns false

MimeKit Version: 3.3.0

[jstedfast]

Good catch, thanks!