RFC 2822 defines the Date: header. It declares the header a required
 part of an email message. The syntax for date headers is clearly laid
 out. Still, even a perfectly planned world has storms. The truth is, many
 programs get it wrong. Very wrong. Or, they don't include a Date: header
 at all. This often forces you to look elsewhere for the date, and hoping
 to find something.
 .
 For this reason, the tedious process of looking for a valid date has been
 encapsulated in this software. Further, the process of creating RFC
 compliant date strings is also found in this software.