Is there an add-on, for Gmail, that allows you to...  ...schedule an email to send later?  ...send an email, when you write it, but it doesn't actually send until a certain time?  ...set "work hours/days" and only allows emails to enter recipients inbox during that time?    User story:  I am a user, who desires to respect everyone's off time, and I would like some way to send emails when they are on my mind, without setting precedent that it is okay or expected to do this.