Function mz_coord::coord::fast_path_peek::create_plan

pub fn create_plan(
    dataflow_plan: DataflowDescription<Plan>, 
    view_id: GlobalId, 
    index_id: GlobalId, 
    index_key: Vec<MirScalarExpr>, 
    index_permutation: HashMap<usize, usize>, 
    index_thinned_arity: usize
) -> Result<Plan, CoordError>

Determine if the dataflow plan can be implemented without an actual dataflow.

If the optimized plan is a Constant or a Get of a maintained arrangement, we can avoid building a dataflow (and either just return the results, or peek out of the arrangement, respectively).