process.swift

    private func process(_ samples: [HKQuantitySample], type: HKQuantityTypeIdentifier) {
        var lastHeartRate = 0.0
        
        for sample in samples {
            if type == .heartRate {
                lastHeartRate = sample.quantity.doubleValue(for: heartRateQuantity)
            }
            
            self.value = Int(lastHeartRate)
        }
    }