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docs: correct example in MissedTickBehavior::Burst #4713

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merged 1 commit into from May 22, 2022
Merged

docs: correct example in MissedTickBehavior::Burst #4713

merged 1 commit into from May 22, 2022

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ekzhang
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@ekzhang ekzhang commented May 22, 2022

Motivation

Hi there! While looking at the docs for MissedTickBehavior, I noticed that the comments in the code example have a very small error.

use tokio::time::{interval, Duration};

let mut interval = interval(Duration::from_millis(50));

task_that_takes_200_millis().await;
// The `Interval` has missed a tick

// Since we have exceeded our timeout, this will resolve immediately
interval.tick().await;

// Since we are more than 100ms after the start of `interval`, this will
// also resolve immediately.
interval.tick().await;

// Also resolves immediately, because it was supposed to resolve at
// 150ms after the start of `interval`
interval.tick().await;

// Resolves immediately
interval.tick().await;

// Since we have gotten to 200ms after the start of `interval`, this
// will resolve after 50ms
interval.tick().await;

The code example forgets that the first interval.tick() resolves immediately after creation. So if you print out all of the elapsed times after each tick, you'll see that they all resolve immediately.

Here's a playground link that shows the issue. If you run this code then you'll see the following output:

1. 201.484664ms
2. 201.523575ms
3. 201.528885ms
4. 201.535065ms
5. 201.555235ms

However, if you uncomment line 11, which has the extra interval.tick().await; that this PR proposes, then the output changes to what would be expected in the docs:

1. 202.916324ms
2. 203.013206ms
3. 203.050227ms
4. 203.094128ms
5. 251.418813ms

Solution

This PR fixes the issue by just adding one more line with interval.tick().await at the beginning of the example, before the long task.

@Darksonn Darksonn added A-tokio Area: The main tokio crate M-time Module: tokio/time labels May 22, 2022
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Thanks.

@Darksonn Darksonn merged commit 323b63f into tokio-rs:master May 22, 2022
43 checks passed
@ekzhang ekzhang deleted the patch-1 branch May 22, 2022 22:11
crapStone pushed a commit to Calciumdibromid/CaBr2 that referenced this pull request Jun 11, 2022
This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [tokio](https://tokio.rs) ([source](https://github.com/tokio-rs/tokio)) | dependencies | minor | `1.18.2` -> `1.19.1` |
| [tokio](https://tokio.rs) ([source](https://github.com/tokio-rs/tokio)) | dev-dependencies | minor | `1.18.2` -> `1.19.1` |

---

### Release Notes

<details>
<summary>tokio-rs/tokio</summary>

### [`v1.19.1`](https://github.com/tokio-rs/tokio/releases/tag/tokio-1.19.1)

[Compare Source](tokio-rs/tokio@tokio-1.19.0...tokio-1.19.1)

##### 1.19.1 (June 5, 2022)

This release fixes a bug in `Notified::enable`. ([#&#8203;4747])

[#&#8203;4747]: tokio-rs/tokio#4747

### [`v1.19.0`](https://github.com/tokio-rs/tokio/releases/tag/tokio-1.19.0)

[Compare Source](tokio-rs/tokio@tokio-1.18.2...tokio-1.19.0)

##### 1.19.0 (June 3, 2022)

##### Added

-   runtime: add `is_finished` method for `JoinHandle` and `AbortHandle` ([#&#8203;4709])
-   runtime: make global queue and event polling intervals configurable ([#&#8203;4671])
-   sync: add `Notified::enable` ([#&#8203;4705])
-   sync: add `watch::Sender::send_if_modified` ([#&#8203;4591])
-   sync: add resubscribe method to broadcast::Receiver ([#&#8203;4607])
-   net: add `take_error` to `TcpSocket` and `TcpStream` ([#&#8203;4739])

##### Changed

-   io: refactor out usage of Weak in the io handle ([#&#8203;4656])

##### Fixed

-   macros: avoid starvation in `join!` and `try_join!` ([#&#8203;4624])

##### Documented

-   runtime: clarify semantics of tasks outliving `block_on` ([#&#8203;4729])
-   time: fix example for `MissedTickBehavior::Burst` ([#&#8203;4713])

##### Unstable

-   metrics: correctly update atomics in `IoDriverMetrics` ([#&#8203;4725])
-   metrics: fix compilation with unstable, process, and rt, but without net ([#&#8203;4682])
-   task: add `#[track_caller]` to `JoinSet`/`JoinMap` ([#&#8203;4697])
-   task: add `Builder::{spawn_on, spawn_local_on, spawn_blocking_on}` ([#&#8203;4683])
-   task: add `consume_budget` for cooperative scheduling ([#&#8203;4498])
-   task: add `join_set::Builder` for configuring `JoinSet` tasks ([#&#8203;4687])
-   task: update return value of `JoinSet::join_one` ([#&#8203;4726])

[#&#8203;4498]: tokio-rs/tokio#4498

[#&#8203;4591]: tokio-rs/tokio#4591

[#&#8203;4607]: tokio-rs/tokio#4607

[#&#8203;4624]: tokio-rs/tokio#4624

[#&#8203;4656]: tokio-rs/tokio#4656

[#&#8203;4671]: tokio-rs/tokio#4671

[#&#8203;4682]: tokio-rs/tokio#4682

[#&#8203;4683]: tokio-rs/tokio#4683

[#&#8203;4687]: tokio-rs/tokio#4687

[#&#8203;4697]: tokio-rs/tokio#4697

[#&#8203;4705]: tokio-rs/tokio#4705

[#&#8203;4709]: tokio-rs/tokio#4709

[#&#8203;4713]: tokio-rs/tokio#4713

[#&#8203;4725]: tokio-rs/tokio#4725

[#&#8203;4726]: tokio-rs/tokio#4726

[#&#8203;4729]: tokio-rs/tokio#4729

[#&#8203;4739]: tokio-rs/tokio#4739

</details>

---

### Configuration

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🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied.

 **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about these updates again.

---

 - [x] <!-- rebase-check -->If you want to rebase/retry this PR, click this checkbox.

---

This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).

Co-authored-by: cabr2-bot <cabr2.help@gmail.com>
Reviewed-on: https://codeberg.org/Calciumdibromid/CaBr2/pulls/1394
Reviewed-by: crapStone <crapstone@noreply.codeberg.org>
Co-authored-by: Calciumdibromid Bot <cabr2_bot@noreply.codeberg.org>
Co-committed-by: Calciumdibromid Bot <cabr2_bot@noreply.codeberg.org>
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