public override async Task <bool> WriteAsync(HealthDataType healthDataType, double value, DateTime start, DateTime?end = null) { if (end == null) { end = start; } var healthKit = healthDataType.ToHealthKit(); if (healthKit.HKType == HKTypes.Category) { var type = HKCategoryType.Create(healthDataType.ToHealthKit().CategoryTypeIdentifier); var sample = HKCategorySample.FromType(type, (nint)value, (NSDate)start, (NSDate)end); var(success, error) = await _healthStore.SaveObjectAsync(sample).ConfigureAwait(false); return(success); } else if (healthKit.HKType == HKTypes.Quantity) { var type = HKQuantityType.Create(healthDataType.ToHealthKit().QuantityTypeIdentifier); var quantity = HKQuantity.FromQuantity(healthDataType.ToHealthKit().Unit, value); var sample = HKQuantitySample.FromType(type, quantity, (NSDate)start, (NSDate)end); var(success, error) = await _healthStore.SaveObjectAsync(sample).ConfigureAwait(false); return(success); } else { throw new NotSupportedException(); } }