#[derive(PreferDataFrame)]Expand description
Derive PreferDataFrame: when a type implements both IntoDataFrame (via DataFrameRow)
and other conversion paths, this selects data.frame as the default IntoR conversion.
§Example
ⓘ
#[derive(DataFrameRow, PreferDataFrame)]
struct Obs { time: f64, value: f64 }
// IntoR produces data.frame(time = ..., value = ...)