private func calculateNextRefresh() -> Date?
{
    let now = Date()
    let calendar = Calendar.current
    var dateComponents = DateComponents()
    dateComponents.year = calendar.component(.year, from: now)
    dateComponents.month = calendar.component(.month, from: now)
    dateComponents.day = calendar.component(.day, from: now) + 1
    dateComponents.hour = 8
    dateComponents.minute = 0
    dateComponents.second = 0
    
    dateComponents.timeZone = TimeZone(identifier: "America/Los_Angeles")
    
    return calendar.date(from: dateComponents)
}