Function map_blocks_in 

pub fn map_blocks_in<T, F>(
    plan: BlockPlan,
    context: &ExecutionContext,
    block: F,
) -> Result<Vec<T>, WorkerPanicked>
where
    T: Send,
    F: Fn(usize, Range<usize>) -> T + Sync,

Runs a block plan on the pool and worker budget owned by an execution graph.

Concurrent and nested operations share the same bounded native pool. The fixed block plan and final block-index ordering preserve deterministic reductions independently of scheduling.

Errors

Returns WorkerPanicked if a native task panics.