// Application/Interfaces/IFuelService.cs
public interface IFuelService
{
    Task<IReadOnlyList<FuelReading>> GetAllReadingsAsync(CancellationToken cancellationToken = default);
    Task<FuelReading?> GetByIdAsync(Guid id, CancellationToken cancellationToken = default);
}

// Application/Services/FuelService.cs
public class FuelService : IFuelService
{
    private readonly ILogger<FuelService> _logger;
    private readonly JsonFileStore _fileStore;

    public FuelService(ILogger<FuelService> logger, JsonFileStore fileStore)
    {
        _logger = logger;
        _fileStore = fileStore;
    }

    public async Task<IReadOnlyList<FuelReading>> GetAllReadingsAsync(CancellationToken cancellationToken = default)
    {
        var readings = await _fileStore.LoadAsync<List<FuelReading>>("fuel.json", cancellationToken);
        return readings?.AsReadOnly() ?? new List<FuelReading>().AsReadOnly();
    }
}

// Core/Entities/FuelReading.cs
public class FuelReading
{
    public Guid Id { get; set; }
    public double Level { get; set; }
    public DateTime Timestamp { get; set; }
    public bool IsActive { get; set; } = true;  // Soft delete pattern
}

public class MyPlugin : ISensorPlugin, IDisposable
{
    private readonly ILogger<MyPlugin> _logger;
    private readonly Dictionary<string, double> _values = new();
    private bool _disposed;

    public string Name => "My Plugin";
    public string Version => "1.0.0";

    public async Task InitializeAsync(Dictionary<string, object> config, CancellationToken ct = default)
    {
        _logger.LogInformation("Initializing {PluginName}", Name);
        // Setup from config dictionary
    }

    public Task<double> ReadValueAsync(string sensorId, CancellationToken ct = default)
        => Task.FromResult(_values.GetValueOrDefault(sensorId, 0.0));

    public void Dispose()
    {
        if (_disposed) return;
        _disposed = true;
        // Cleanup
    }
}

await _hubContext.Clients.Group("tanks").SendAsync(
    "TankLevelUpdated", tankId, currentLevel, tankName, cancellationToken);