Optimize watchOS CMSensorDataList parsing

I am trying to parse CMSensorDataList in watchOS. The maximum batch of data is comprised of 30 minutes. The sampling rate is 50Hz, which makes it 90,000 records for 30 minutes. We iterate over each item and finally write the data to a CSV file. As this is a slow processing keeping in view the execution limits of watchOS, the process suspends when app goes to the background. This way, it takes too much time to parse a significant time data. My question is, is there a way we can serialize this CMSensorDataList as a whole and transfer it to the phone using WCSession? Or is there another effective way to achieve this?

Optimize watchOS CMSensorDataList parsing
 
 
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