Code base refactor - Data class

This issue should be for discussing the requirements of a data class. Here is a preliminary list of requirements:

Functional Requirements:

Data Backend Support: Should support multiple data backends for holding and providing data.
Interprocess Communication (IPC) Support: Should be able to communicate with external processes (e.g. other programming languages) using different IPC mechanisms.
Data Persistence: Should provide functionality to load and save data using various methods.
Synthetic Data Handling: Should support the generation of synthetic data, currently used primarily for unit tests and prototyping.

Technical Requirements

Should support Arrow, Andromeda, DataTable as data backends.
Should support Andromeda, Arrow Flight, Arrow Feather for IPC.

Possible architecture:

classDiagram
    class Data {
        -.data
        -.meta_data
        -.backend: DataBackend
        +data()
        +metadata()
        +setBackend(backend: DataBackend)
        +load(file_path) : uses
        +save(file_path) : uses
        +to_ipc(ipc: IPC) : uses
        +from_ipc(ipc: IPC) : uses
    }

    class DataBackend {
        <<abstract>>
    }

    class DataBackend-Arrow
    class DataBackend-Andromeda
    class DataBackend-DataTable

    Data --> DataBackend
    DataBackend <|-- DataBackend-Arrow
    DataBackend <|-- DataBackend-Andromeda
    DataBackend <|-- DataBackend-DataTable

    class DataPersistence {
      <<abstract>>
      +load()
      +save()
    }

    class DataPersistence-LocalFile {
      +load(file_path)
      +save(.data, file_path)
    }

    class DataPersistence-Database {
      +load(connection_details)
    }

    class DataPersistence-Synthetic {
      +load()
    }

    Data --> DataPersistence
    DataPersistence <|-- DataPersistence-Database
    DataPersistence <|-- DataPersistence-LocalFile
    DataPersistence <|-- DataPersistence-Synthetic

    class IPC {
        <<abstract>>
        +doPut()
        +doGet()
        +doExchange()
    }

    class IPC-ArrowFlight
    class IPC-ArrowFeather
    class IPC-Andromeda

    IPC <|-- IPC-ArrowFlight
    IPC <|-- IPC-ArrowFeather
    IPC <|-- IPC-Andromeda

    Data --> IPC
    class PyData {
        +to_ipc(ipc: IPC)
        +from_ipc(ipc: IPC)
    }

    class RustData {
        +to_ipc(ipc: IPC)
        +from_ipc(ipc: IPC)
    }

    PyData --> IPC
    RustData --> IPC

OHDSI / PatientLevelPrediction

Code base refactor - Data class #469