功能开关

public interface IFeatureStore
{
    Task<bool> IsEnabledAsync(string featureName,
        string? tenantId = null,
        CancellationToken ct = default);
}

// 默认：始终返回 false（特性禁用）
public class UnavailableFeatureStore : IFeatureStore
{
    public Task<bool> IsEnabledAsync(string featureName, ...) => Task.FromResult(false);
}

if (await featureStore.IsEnabledAsync("new-dashboard", tenantId))
{
    // 提供新仪表盘
}
else
{
    // 提供旧版仪表盘
}