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: callback.rs
    path of file: ./repos/leptos/leptos_reactive/src
    
    the code of the file until where you have to start completion: //! Callbacks define a standard way to store functions and closures. They are useful
//! for component properties, because they can be used to define optional callback functions,
//! which generic props donâ€™t support.
//!
//! # Usage
//! Callbacks can be created manually from any function or closure, but th
    
    fn callback_from_html() {
        let rt = create_runtime();
        use leptos::{
            html::{AnyElement, HtmlElement},
            *,
        };

        let _callback: Callback<String, HtmlElement<AnyElement>> =
            (|x: String| {
                view! {
                    <h1>{x}</h1>
                }
            })
            .into();
        rt.dispose();
    }