You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: mod.rs
    path of file: ./repos/risinglight/src/executor
    
    the code of the file until where you have to start completion: // Copyright 2024 RisingLight Project Authors. Licensed under Apache-2.0.

//! # Execution Model
//!
//! The execution engine executes the query in a Vectorized Volcano model.
//!
//! # Async Stream
//!
//! Each executor is an async-stream that produces a stream of values asynchronously.
//!
//! To w
    
    fn resolve_column_index(&self, expr: Id, plan: Id) -> RecExpr {
        let schema = &self.egraph[plan].data.schema;
        self.node(expr).build_recexpr(|id| {
            if let Some(idx) = schema.iter().position(|x| *x == id) {
                return Expr::ColumnIndex(ColumnIndex(idx as _));
            }
            match self.node(id) {
                Expr::Column(c) => panic!("column {c} not found from input"),
                e => e.clone(),
            }
        })
    }