Add FileSystem serdes for parity with JavaScript: https://github.com/aws/aws-durable-execution-sdk-js/blob/main/packages/aws-durable-execution-sdk-js/src/utils/serdes/filesystem-serdes.ts
Add FileSystem serdes for parity with JavaScript:
https://github.com/aws/aws-durable-execution-sdk-js/blob/main/packages/aws-durable-execution-sdk-js/src/utils/serdes/filesystem-serdes.ts