Merge #99

99: Bump tokio from 0.2.4 to 0.2.6 r=sopium a=dependabot-preview[bot]

Bumps [tokio](/~https://github.com/tokio-rs/tokio) from 0.2.4 to 0.2.6.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a href="/~https://github.com/tokio-rs/tokio/releases">tokio's releases</a>.</em></p>
<blockquote>
<h2>Tokio v0.2.6</h2>
<p>This release fixes an API regression introduced as part of v0.2.5.</p>
<h3>Fixes</h3>
<ul>
<li><code>fs::File::seek</code> API regression (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/1991">#1991</a>).</li>
</ul>
<h2>Tokio v0.2.5</h2>
<p>Includes new APIs, utilities, and fixes. Some highlights:</p>
<h3><code>tokio::sync::broadcast</code></h3>
<p>A multi-producer, multi-consumer channel where each sent value is sent to <strong>all</strong> consumers (fan-out). The channel is <strong>bounded</strong> and when consumers lag, they will receive an error indicating they have lagged too far behind.</p>
<pre lang="rust"><code>use tokio::sync::broadcast;
<p>#[tokio::main]
async fn main() {
let (tx, mut rx1) = broadcast::channel(16);
let mut rx2 = tx.subscribe();</p>
<pre><code>tokio::spawn(async move {
    assert_eq!(rx1.recv().await.unwrap(), 10);
    assert_eq!(rx1.recv().await.unwrap(), 20);
});

tokio::spawn(async move {
    assert_eq!(rx2.recv().await.unwrap(), 10);
    assert_eq!(rx2.recv().await.unwrap(), 20);
});

tx.send(10).unwrap();
tx.send(20).unwrap();
</code></pre>
<p>}
</code></pre></p>
<p>Senders never block. When the channel is full, the oldest value still held by the channel is overwritten. This tends to be the desired behavior in order to prevent slow consumers from blocking the entire system. However, you can use a <code>Semaphore</code> (also added in this release) to ensure that all consumers see all messages.</p>
<h3><code>tokio::sync::Semaphore</code></h3>
<p>A counting synchronization primitive. It is used to limit a critical section to 1 or more concurrent tasks. For example, assume we wish to limit the number of in-flight database queries, we could do something like:</p>
<pre lang="rust"><code>struct MyDbClient {
    db: MyDbHandle,
    semaphore: tokio::sync:Semaphore,
}
<p>async fn query(client: &amp;MyDbClient, query: Query) -&gt; QueryResult {
let _permit = client.semaphore.acquire().await;
&lt;/tr&gt;&lt;/table&gt; ... (truncated)
</code></pre></p>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a href="/~https://github.com/tokio-rs/tokio/commit/248bf2144f4fa2792f430acec67bd5763236fabd"><code>248bf21</code></a> prepare v0.2.6 release (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/1995">#1995</a>)</li>
<li><a href="/~https://github.com/tokio-rs/tokio/commit/93ab70a9a0eca676ef718f02482d3fa0bdd760fd"><code>93ab70a</code></a> fs: add deprecated fs::File::seek fn (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/1991">#1991</a>)</li>
<li><a href="/~https://github.com/tokio-rs/tokio/commit/58b5abdb99f113152e9953b0576c4c2fd0aaab99"><code>58b5abd</code></a> update connect example (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/1787">#1787</a>)</li>
<li><a href="/~https://github.com/tokio-rs/tokio/commit/2d78cfe56ac14f384e26278951b52099d33bd797"><code>2d78cfe</code></a> chore: prepare v0.2.5 release (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/1984">#1984</a>)</li>
<li><a href="/~https://github.com/tokio-rs/tokio/commit/4c645866ef4ea5b0ef8c7852281a09b2f96d969b"><code>4c64586</code></a> stream: add <code>next</code> and <code>map</code> utility fn (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/1962">#1962</a>)</li>
<li><a href="/~https://github.com/tokio-rs/tokio/commit/b0836ece7aa5219e9e40355d0eb784baffc7b6c6"><code>b0836ec</code></a> sync: encapsulate TryLockError variants (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/1980">#1980</a>)</li>
<li><a href="/~https://github.com/tokio-rs/tokio/commit/0c0f68201037af3fbaac6ca29a9806e392593d89"><code>0c0f682</code></a> Improve runtime threading options docs</li>
<li><a href="/~https://github.com/tokio-rs/tokio/commit/b24ad9fe861ce01add2c6533149f643e38537f59"><code>b24ad9f</code></a> rt: add configuration for core threads and max threads (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/1977">#1977</a>)</li>
<li><a href="/~https://github.com/tokio-rs/tokio/commit/7c010ed030d0084d38451bbebf727c6695c2dbac"><code>7c010ed</code></a> sync: add broadcast channel (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/1943">#1943</a>)</li>
<li><a href="/~https://github.com/tokio-rs/tokio/commit/42c942de1433c37946f81d185459b8ee54928d3d"><code>42c942d</code></a> Fix ROADMAP link (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/1981">#1981</a>)</li>
<li>Additional commits viewable in <a href="/~https://github.com/tokio-rs/tokio/compare/tokio-0.2.4...tokio-0.2.6">compare view</a></li>
</ul>
</details>
<br />


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Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Cargo.toml

@@ -58,7 +58,7 @@ num-traits = "0.2.10"
 tokio-util = { version = "0.2.0", features = ["codec"] }
 
 [dependencies.tokio]
-version = "0.2.4"
+version = "0.2.6"
 features = [
     "io-std",
     "io-driver",

src/cli/real_main.rs

@@ -178,7 +178,7 @@ impl Options {
             let mut rt = tokio::runtime::Builder::new()
                 .enable_all()
                 .threaded_scheduler()
-                .num_threads(threads)
+                .core_threads(threads)
                 .build()?;
             rt.block_on(cli::run(config, notify, stop_rx))
         } else {

src/main.rs

@@ -158,7 +158,7 @@ fn main() {
             .enable_all()
             // Have to use threaded because we use `block_in_place`.
             .threaded_scheduler()
-            .num_threads(1)
+            .core_threads(1)
             .build()
             .context("build tokio runtime")?;