To toggle the mod, there is a customizable key (default Pause). You can use Generic Mod Config Menu to change it, or edit the config file.
Technical
Requires SDV 1.5.5+
Requires SMAPI, uses Harmony.
Compatible with Mod Updater for automatic updates.
Code is at https://github.com/aedenthorn/StardewValleyMods.
If you want to complain or ask for help or help me test my mods, you can visit my Discord server.
A list of all my mods for Stardew Valley is available at https://www.nexusmods.com/stardewvalley/articles/895.