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: entrypoint.rs
    path of file: ./repos/perseus/packages/perseus-macro/src
    
    the code of the file until where you have to start completion: use proc_macro2::TokenStream;
use quote::quote;
use syn::parse::{Parse, ParseStream};
use syn::{Attribute, Block, Generics, Item, ItemFn, Path, Result, ReturnType, Type};

/// A function that can be made into a Perseus app's entrypoint.
///
/// The signature of this functi
    
pub fn engine_main_impl(input: EngineMainFn) -> TokenStream {
    let EngineMainFn { block, attrs, .. } = input;

    // We split the user's function out into one for the browser and one for the
    // engine (all based around the default engine)
    let output = quote! {
        // The engine-specific `main` function
        #[cfg(engine)]
        #[tokio::main]
        #(#attrs)*
        async fn main() {
            #block
        }
    };

    output
}