mbTiles download and store on device

I have a project based app. Each project will have its own mbtiles file for offline use within a leaflet/mapbox map.

I want my users to click a button to download the current project’s mbtiles file, and save it on the device (i.e. I want to cache the mbtiles file).

Does anybody have a suggestion for the reliable saving of a 100MB+ file to the device? I would only ever keep one mbtiles file on the device.