fn plan_copy_to_expr(
scx: &StatementContext<'_>,
select_plan: SelectPlan,
desc: RelationDesc,
to: &Expr<Aug>,
format: CopyFormat,
options: CopyOptionExtracted,
) -> Result<Plan, PlanError>
fn plan_copy_to_expr(
scx: &StatementContext<'_>,
select_plan: SelectPlan,
desc: RelationDesc,
to: &Expr<Aug>,
format: CopyFormat,
options: CopyOptionExtracted,
) -> Result<Plan, PlanError>