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: base.rs
    path of file: ./repos/burn/crates/burn-jit/src/kernel/matmul/tune
    
    the code of the file until where you have to start completion: use burn_compute::tune::{AutotuneOperation, AutotuneOperationSet};
use burn_tensor::{Element, ElementConversion};

use crate::{
    compute::JitAutotuneKey,
    element::JitElement,
    kernel::{matmul::utils::init_matmul_ou
    
    fn fastest(self: Box<Self>, fastest_index: usize) -> Box<dyn AutotuneOperation> {
        match fastest_index {
            0 => Box::new(MemoryCoalescingMatmulDefault::new(
                self.lhs, self.rhs, self.out,
            )),
            1 => Box::new(MemoryCoalescingMatmulW16x16::new(
                self.lhs, self.rhs, self.out,
            )),
            2 => Box::new(Vec4TilingMatmulDefault::new(self.lhs, self.rhs, self.out)),
            3 => Box::new(Vec4TilingMatmulUnpaddedDefault::new(
                self.lhs, self.rhs, self.out,
            )),
            _ => panic!("Fastest index is out of bound"),
        }
    }