Function render_auto_with_spec 

pub fn render_auto_with_spec<T: Serialize>(
    template: &str,
    data: &T,
    theme: &Theme,
    mode: OutputMode,
    spec: Option<&FlatDataSpec>,
) -> Result<String, Error>

Auto-dispatches with granular control over structured output.

Similar to render_auto, but allows passing an optional FlatDataSpec. This is particularly useful for controlling CSV output structure (columns, headers) instead of relying on automatic JSON flattening.

Arguments

• template - A minijinja template string
• data - Any serializable data to render or serialize
• theme - Theme definitions for the style filter
• mode - Output mode determining the output format
• spec - Optional FlatDataSpec for defining CSV/Table structure