Gmail has a very useful function used here in the company which is "Schedule Send". I create the message reply to the client, but choose the date and time I want to send that reply.
This would be very useful in the form of answers from the support / helpdesk.
Because sometimes we read, but we do not want to give the immediate response to the customer, so that it does not become a chat.
If we have the option to type in the response, and scheduling when it will be posted to the customer would be very helpful.