Function execute 

pub fn execute(
    plan: &ExecutionPlan,
    ctx: &mut Context,
    catalog: &NodeCatalog,
    cache: &dyn CacheStore,
) -> Result<()>

Execute a compiled plan.

Every arm delegates. The variants that need real work — a node, a loop, a branch, a fan-out — each have a function, so this reads as the list of things a plan can be rather than as their implementations.