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/vim-clap/crates/maple_core/src/stdio_server
    
    the code of the file until where you have to start completion: mod diagnostics_worker;
mod input;
mod job;
mod plugin;
mod provider;
mod request_handler;
mod service;
mod vim;
mod winbar;

pub 
    
    async fn do_process_request(&self, rpc_request: RpcRequest) -> Result<Option<Value>, Error> {
        let msg = rpc_request;

        let value = match msg.method.as_str() {
            "preview/file" => Some(request_handler::preview_file(msg).await?),
            "quickfix" => Some(request_handler::preview_quickfix(msg).await?),
            _ => Some(json!({
                "error": format!("Unknown request: {}", msg.method)
            })),
        };

        Ok(value)
    }