Function timeStringNullable

riverdriver/riversqlite/river_sqlite_driver.go:1685–1692

This is kind of unfortunate, but I've found it the easiest way to encode an optional date/time. Unfortunately sqlc (or the driver? not sure) will write a `*time.Time` as an integer (presumably a Unix timestamp), and then be unable to scan it back into a `time.Time`. This workaround has us cast input

(t *time.Time)

// no date/time type, only `integer` or `text`) to make sure it's in our desired
// target format.
func timeStringNullable(t *time.Time) *string {
	if t == nil {
		return nil
	}

	str := timeString(*t)
	return &str
}