Exploring the Tokio framework for async programming

Before we explore what Tokio is and how it works, we should try to execute some async code in normal Rust. Throughout this chapter, we will be building a basic simulation using Tokio. Therefore, the Tokio code that we will be writing is in the simulation directory as its own Cargo project. Seeing as we are running async functions in our Rust server code to process views, we can see if we can execute a basic async function in our main function in the main.rs file with the following code:

async fn hello() {
    println!("Hello, world!");
}
fn main() {
    hello();
}

This looks simple enough; however, if we try to run our main function, we get the following output:

warning: unused implementer of `Future` that must be used
 --> src/main.rs:9:5
  |
9 |     hello();
  |     ^^^^^^^^
  |
  ...