Say I have an email class that has the following properties:

```
public string From { get; set; }
public string To { get; set; }
public string Subject { get; set; }
public string Body { get; set; }
public Dictionary<string, byte[]> Attachments { get; set; }

```

I need to calculate the size of the email and if it is less than 10MB email it otherwise send the content as a fax (to prevent it being bounced from its destination). 

I can calculate the size of attachments relatively easily. 

Is there an accurate way to calculate the entire email size? I'm guessing I'll need to add the size of the strings as well as any header information that will be appended?