[Vitaly]

I use my own simple google apps script. Has a benefit of working with any mail program: https://github.com/vitaly/gmail-later

With gmail keyboard shortcuts work like a charm.

[rahimnathwani]

This seems like a cool way to hide received emails until some time in the future.

I read the OP's ambiguous question as meaning they wanted to write emails now, which would be sent later.