This function may be invoked from multiple threads simultaneously for different emails for parallel processing.

Example below shows how to extract the subject without spaces to a new field called {SUBJECT_NO_SPACES}.

public void ExtractFromEmail(string account, string ruleName, string uniqueID, MailMessage message)
{
    var result = new Dictionary<string, object>();
    result.Add("{SUBJECT_NO_SPACES}", message.Subject.Replace(" ", ""));
    return result;
}