How to access to log event?

how to access to log event
for example, how to add log event to mail message?

In Try catch activity, I Invoked workflow
In Catches, I have “Send SMTP Mail Message”, exception.Source as body

in workflow I’ve created log message “New log message”
after Invoked workflow, I see log event “New log message” in Output window

how to access to Log event: “New log message” and add it to the mail body ?

thank you