use cargo add when adding dependencies

This picks specific latest x.y.z version available, which is generally
what most users should be doing when writing new applications rather
than choosing a general version. This builds upon the tokio website
dependencies being automatically updated by dependabot. If these fail to
build in a particular version, then these cargo add commands should be
temporarily changed to pin specific versions. However, this should be
rare.

Author: joshka

content/tokio/topics/tracing-next-steps.md

@@ -12,9 +12,8 @@ performance issues during the development process.
 For instance, to use tokio-console in [the mini-redis project](https://github.com/tokio-rs/mini-redis),
 you need to enable the `tracing` feature for the Tokio package:
 
-```toml
-# Update the tokio import in your Cargo.toml
-tokio = { version = "1", features = ["full", "tracing"] }
+```bash
+cargo add tokio --features full,tracing
 ```
 
 Note: The `full` feature doesn't enable `tracing`.
@@ -23,9 +22,8 @@ You'll also need to add a dependency on the `console-subscriber` package. This
 crate provides a `Subscriber` implementation that will replace the one currently
 used by mini-redis:
 
-```toml
-# Add this to the dependencies section of your Cargo.toml
-console-subscriber = "0.1.5"
+```bash
+cargo add console-subscriber
 ```
 
 Finally, in `src/bin/server.rs`, replace the call to `tracing_subscriber` with
@@ -128,16 +126,16 @@ It will look like this:
 
 We'll come back to this page once we have some trace data generated and sent.
 
-To set up mini-redis, we'll first need to add a few dependencies. Update your
-`Cargo.toml` with the following:
+To set up mini-redis, we'll first need to add a few dependencies. Add the
+following dependencies to your `Cargo.toml` file:
 
-```toml
+```bash
 # Implements the types defined in the Otel spec
-opentelemetry = "0.17.0"
+cargo add opentelemetry
 # Integration between the tracing crate and the opentelemetry crate
-tracing-opentelemetry = "0.17.2" 
+cargo add tracing-opentelemetry
 # Allows you to export data to Jaeger
-opentelemetry-jaeger = "0.16.0"
+cargo add opentelemetry-jaeger
 ```
 
 Now, in `src/bin/server.rs`, add the following imports:

content/tokio/tutorial/async.md

@@ -499,10 +499,10 @@ implementors, but requires a bunch of unsafe boilerplate code. Instead of using
 provided by the [`futures`] crate. This allows us to implement a simple trait to
 expose our `Task` struct as a waker.
 
-Add the following dependency to your `Cargo.toml` to pull in `futures`.
+Add the `futures` dependency to your `Cargo.toml` file:
 
-```toml
-futures = "0.3"
+```bash
+cargo add futures
 ```
 
 Then implement [`futures::task::ArcWake`][`ArcWake`].

content/tokio/tutorial/hello-tokio.md

@@ -13,17 +13,17 @@ then read back the key. This will be done using the Mini-Redis client library.
 Let's start by generating a new Rust app:
 
 ```bash
-$ cargo new my-redis
-$ cd my-redis
+cargo new my-redis
+cd my-redis
 ```
 
 ## Add dependencies
 
-Next, open `Cargo.toml` and add the following right below `[dependencies]`:
+Next, add the following dependencies to your `Cargo.toml` file:
 
-```toml
-tokio = { version = "1", features = ["full"] }
-mini-redis = "0.4"
+```bash
+cargo add tokio --features full
+cargo add mini-redis
 ```
 
 ## Write the code
@@ -55,13 +55,13 @@ async fn main() -> Result<()> {
 Make sure the Mini-Redis server is running. In a separate terminal window, run:
 
 ```bash
-$ mini-redis-server
+mini-redis-server
 ```
 
 If you have not already installed mini-redis, you can do so with
 
 ```bash
-$ cargo install mini-redis
+cargo install mini-redis
 ```
 
 Now, run the `my-redis` application:

content/tokio/tutorial/shared-state.md

@@ -30,11 +30,10 @@ the underlying data. Instead, a `Bytes` instance is a reference-counted handle
 to some underlying data. The `Bytes` type is roughly an `Arc<Vec<u8>>` but with
 some added capabilities.
 
-To depend on `bytes`, add the following to your `Cargo.toml` in the
-`[dependencies]` section:
+Add the `bytes` dependency to your `Cargo.toml` file:
 
-```toml
-bytes = "1"
+```bash
+cargo add bytes
 ```
 
 [`bytes`]: https://docs.rs/bytes/1/bytes/struct.Bytes.html
@@ -154,6 +153,7 @@ async fn process(socket: TcpStream, db: Db) {
 # Holding a `MutexGuard` across an `.await`
 
 You might write code that looks like this:
+
 ```rust
 use std::sync::{Mutex, MutexGuard};
 
@@ -165,8 +165,10 @@ async fn increment_and_do_stuff(mutex: &Mutex<i32>) {
 } // lock goes out of scope here
 # async fn do_something_async() {}
 ```
+
 When you try to spawn something that calls this function, you will encounter the
 following error message:
+
 ```text
 error: future cannot be sent between threads safely
    --> src/lib.rs:13:5
@@ -191,11 +193,13 @@ note: future is not `Send` as this value is used across an await
 8   | }
     | - `mut lock` is later dropped here
 ```
+
 This happens because the `std::sync::MutexGuard` type is **not** `Send`. This
 means that you can't send a mutex lock to another thread, and the error happens
 because the Tokio runtime can move a task between threads at every `.await`.
 To avoid this, you should restructure your code such that the mutex lock's
 destructor runs before the `.await`.
+
 ```rust
 # use std::sync::{Mutex, MutexGuard};
 // This works!
@@ -209,7 +213,9 @@ async fn increment_and_do_stuff(mutex: &Mutex<i32>) {
 }
 # async fn do_something_async() {}
 ```
+
 Note that this does not work:
+
 ```rust
 use std::sync::{Mutex, MutexGuard};
 
@@ -223,6 +229,7 @@ async fn increment_and_do_stuff(mutex: &Mutex<i32>) {
 }
 # async fn do_something_async() {}
 ```
+
 This is because the compiler currently calculates whether a future is `Send`
 based on scope information only. The compiler will hopefully be updated to
 support explicitly dropping it in the future, but for now, you must explicitly
@@ -250,6 +257,7 @@ We will discuss some approaches to avoid these issues below:
 
 The safest way to handle a mutex is to wrap it in a struct, and lock the mutex
 only inside non-async methods on that struct.
+
 ```rust
 use std::sync::Mutex;
 
@@ -270,6 +278,7 @@ async fn increment_and_do_stuff(can_incr: &CanIncrement) {
 }
 # async fn do_something_async() {}
 ```
+
 This pattern guarantees that you won't run into the `Send` error, because the
 mutex guard does not appear anywhere in an async function. It also protects you
 from deadlocks, when using crates whose `MutexGuard` implements `Send`.
@@ -288,6 +297,7 @@ The [`tokio::sync::Mutex`] type provided by Tokio can also be used. The primary
 feature of the Tokio mutex is that it can be held across an `.await` without any
 issues. That said, an asynchronous mutex is more expensive than an ordinary
 mutex, and it is typically better to use one of the two other approaches.
+
 ```rust
 use tokio::sync::Mutex; // note! This uses the Tokio mutex