<!DOCTYPE html><htmllang="en"><head><metacharset="utf-8"><metaname="viewport"content="width=device-width, initial-scale=1.0"><metaname="generator"content="rustdoc"><metaname="description"content="Challenge for `WWW-Authenticate` header with HTTP Bearer auth scheme, described in RFC 6750."><metaname="keywords"content="rust, rustlang, rust-lang, Bearer"><title>Bearer in actix_web_httpauth::headers::www_authenticate::bearer - Rust</title><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../../../SourceSerif4-Regular.ttf.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../../../FiraSans-Regular.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../../../FiraSans-Medium.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../../../SourceCodePro-Regular.ttf.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../../../SourceSerif4-Bold.ttf.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../../../SourceCodePro-Semibold.ttf.woff2"><linkrel="stylesheet"href="../../../../normalize.css"><linkrel="stylesheet"href="../../../../rustdoc.css"id="mainThemeStyle"><linkrel="stylesheet"href="../../../../ayu.css"disabled><linkrel="stylesheet"href="../../../../dark.css"disabled><linkrel="stylesheet"href="../../../../light.css"id="themeStyle"><scriptid="default-settings"></script><scriptsrc="../../../../storage.js"></script><scriptdefersrc="sidebar-items.js"></script><scriptdefersrc="../../../../main.js"></script><noscript><linkrel="stylesheet"href="../../../../noscript.css"></noscript><linkrel="alternate icon"type="image/png"href="../../../../favicon-16x16.png"><linkrel="alternate icon"type="image/png"href="../../../../favicon-32x32.png"><linkrel="icon"type="image/svg+xml"href="../../../../favicon.svg"></head><bodyclass="rustdoc struct"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><navclass="mobile-topbar"><buttonclass="sidebar-menu-toggle">☰</button><aclass="sidebar-logo"href="../../../../actix_web_httpauth/index.html"><divclass="logo-container"><imgclass="rust-logo"src="../../../../rust-logo.svg"alt="logo"></div></a><h2></h2></nav><navclass="sidebar"><aclass="sidebar-logo"href="../../../../actix_web_httpauth/index.html"><divclass="logo-container"><imgclass="rust-logo"src="../../../../rust-logo.svg"alt="logo"></div></a><h2class="location"><ahref="#">Bearer</a></h2><divclass="sidebar-elems"><section><h3><ahref="#implementations">Methods</a></h3><ulclass="block"><li><ahref="#method.build">build</a></li></ul><h3><ahref="#trait-implementations">Trait Implementations</a></h3><ulclass="block"><li><ahref="#impl-AsRef%3CBearer%3E-for-Config">AsRef<Bearer></a></li><li><ahref="#impl-Clone-for-Bearer">Clone</a></li><li><ahref="#impl-Debug-for-Bearer">Debug</a></li><li><ahref="#impl-Default-for-Bearer">Default</a></li><li><ahref="#impl-Display-for-Bearer">Display</a></li><li><ahref="#impl-Eq-for-Bearer">Eq</a></li><li><ahref="#impl-Hash-for-Bearer">Hash</a></li><li><ahref="#impl-Ord-for-Bearer">Ord</a></li><li><ahref="#impl-PartialEq%3CBearer%3E-for-Bearer">PartialEq<Bearer></a></li><li><ahref="#impl-PartialOrd%3CBearer%3E-for-Bearer">PartialOrd<Bearer></a></li><li><ahref="#impl-StructuralEq-for-Bearer">StructuralEq</a></li><li><ahref="#impl-StructuralPartialEq-for-Bearer">StructuralPartialEq</a></li><li><ahref="#impl-TryIntoHeaderValue-for-Bearer">TryIntoHeaderValue</a></li></ul><h3><ahref="#synthetic-implementations">Auto Trait Implementations</a></h3><ulclass="block"><li><ahref="#impl-RefUnwindSafe-for-Bearer">RefUnwindSafe</a></li><li><ahref="#impl-Send-for-Bearer">Send</a></li><li><ahref="#impl-Sync-for-Bearer">Sync</a></li><li><ahref="#impl-Unpin-for-Bearer">Unpin</a></li><li><ahref="#impl-UnwindSafe-for-Bearer">UnwindSafe</a></li></ul><h3><ahref="#blanket-implementations">Blanket Implementations</a></h3><ulc
</div></details></div></details></div><h2id="trait-implementations"class="small-section-header">Trait Implementations<ahref="#trait-implementations"class="anchor"></a></h2><divid="trait-implementations-list"><detailsclass="rustdoc-toggle implementors-toggle"open><summary><sectionid="impl-AsRef%3CBearer%3E-for-Config"class="impl has-srclink"><aclass="srclink rightside"href="../../../../src/actix_web_httpauth/extractors/bearer.rs.html#37-41">source</a><ahref="#impl-AsRef%3CBearer%3E-for-Config"class="anchor"></a><h3class="code-header">impl <aclass="trait"href="https://doc.rust-lang.org/nightly/core/convert/trait.AsRef.html"title="trait core::convert::AsRef">AsRef</a><<aclass="struct"href="struct.Bearer.html"title="struct actix_web_httpauth::headers::www_authenticate::bearer::Bearer">Bearer</a>> for <aclass="struct"href="../../../extractors/bearer/struct.Config.html"title="struct actix_web_httpauth::extractors::bearer::Config">Config</a></h3></section></summary><divclass="impl-items"><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.as_ref"class="method trait-impl has-srclink"><aclass="srclink rightside"href="../../../../src/actix_web_httpauth/extractors/bearer.rs.html#38-40">source</a><ahref="#method.as_ref"class="anchor"></a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/nightly/core/convert/trait.AsRef.html#tymethod.as_ref"class="fnname">as_ref</a>(&self) ->&<aclass="struct"href="struct.Bearer.html"title="struct actix_web_httpauth::headers::www_authenticate::bearer::Bearer">Bearer</a></h4></section></summary><divclass='docblock'>Converts this type into a shared reference of the (usually inferred) input type.</div></details></div></details><detailsclass="rustdoc-toggle implementors-toggle"open><summary><sectionid="impl-Clone-for-Bearer"class="impl has-srclink"><aclass="srclink rightside"href="../../../../src/actix_web_httpauth/headers/www_authenticate/challenge/bearer/challenge.rs.html#38">source</a><ahref="#impl-Clone-for-Bearer"class="anchor"></a><h3class="code-header">impl <aclass="trait"href="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html"title="trait core::clone::Clone">Clone</a> for <aclass="struct"href="struct.Bearer.html"title="struct actix_web_httpauth::headers::www_authenticate::bearer::Bearer">Bearer</a></h3></section></summary><divclass="impl-items"><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.clone"class="method trait-impl has-srclink"><aclass="srclink rightside"href="../../../../src/actix_web_httpauth/headers/www_authenticate/challenge/bearer/challenge.rs.html#38">source</a><ahref="#method.clone"class="anchor"></a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#tymethod.clone"class="fnname">clone</a>(&self) -><aclass="struct"href="struct.Bearer.html"title="struct actix_web_httpauth::headers::www_authenticate::bearer::Bearer">Bearer</a></h4></section></summary><divclass='docblock'>Returns a copy of the value. <ahref="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#tymethod.clone">Read more</a></div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.clone_from"class="method trait-impl has-srclink"><spanclass="rightside"><spanclass="since"title="Stable since Rust version 1.0.0">1.0.0</span> · <aclass="srclink"href="https://doc.rust-lang.org/nightly/src/core/clone.rs.html#132-134">source</a></span><ahref="#method.clone_from"class="anchor"></a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#method.clone_from"class="fnname">clone_from</a>(&mut self, source: <aclass="primitive"href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&</a>Self)</h4></section></summary><divclass='docblock'>Performs copy-assignment from <code>source</code>. <ahref="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#method.clone_from">Read more</a></div></detai
by <code>==</code>. <ahref="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialEq.html#tymethod.eq">Read more</a></div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.ne"class="method trait-impl has-srclink"><spanclass="rightside"><spanclass="since"title="Stable since Rust version 1.0.0">1.0.0</span> · <aclass="srclink"href="https://doc.rust-lang.org/nightly/src/core/cmp.rs.html#227">source</a></span><ahref="#method.ne"class="anchor"></a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialEq.html#method.ne"class="fnname">ne</a>(&self, other: <aclass="primitive"href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&</a>Rhs) -><aclass="primitive"href="https://doc.rust-lang.org/nightly/std/primitive.bool.html">bool</a></h4></section></summary><divclass='docblock'>This method tests for <code>!=</code>. The default implementation is almost always
sufficient, and should not be overridden without very good reason. <ahref="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialEq.html#method.ne">Read more</a></div></details></div></details><detailsclass="rustdoc-toggle implementors-toggle"open><summary><sectionid="impl-PartialOrd%3CBearer%3E-for-Bearer"class="impl has-srclink"><aclass="srclink rightside"href="../../../../src/actix_web_httpauth/headers/www_authenticate/challenge/bearer/challenge.rs.html#38">source</a><ahref="#impl-PartialOrd%3CBearer%3E-for-Bearer"class="anchor"></a><h3class="code-header">impl <aclass="trait"href="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialOrd.html"title="trait core::cmp::PartialOrd">PartialOrd</a><<aclass="struct"href="struct.Bearer.html"title="struct actix_web_httpauth::headers::www_authenticate::bearer::Bearer">Bearer</a>> for <aclass="struct"href="struct.Bearer.html"title="struct actix_web_httpauth::headers::www_authenticate::bearer::Bearer">Bearer</a></h3></section></summary><divclass="impl-items"><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.partial_cmp"class="method trait-impl has-srclink"><aclass="srclink rightside"href="../../../../src/actix_web_httpauth/headers/www_authenticate/challenge/bearer/challenge.rs.html#38">source</a><ahref="#method.partial_cmp"class="anchor"></a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialOrd.html#tymethod.partial_cmp"class="fnname">partial_cmp</a>(&self, other: &<aclass="struct"href="struct.Bearer.html"title="struct actix_web_httpauth::headers::www_authenticate::bearer::Bearer">Bearer</a>) -><aclass="enum"href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html"title="enum core::option::Option">Option</a><<aclass="enum"href="https://doc.rust-lang.org/nightly/core/cmp/enum.Ordering.html"title="enum core::cmp::Ordering">Ordering</a>></h4></section></summary><divclass='docblock'>This method returns an ordering between <code>self</code> and <code>other</code> values if one exists. <ahref="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialOrd.html#tymethod.partial_cmp">Read more</a></div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.lt"class="method trait-impl has-srclink"><spanclass="rightside"><spanclass="since"title="Stable since Rust version 1.0.0">1.0.0</span> · <aclass="srclink"href="https://doc.rust-lang.org/nightly/src/core/cmp.rs.html#1119">source</a></span><ahref="#method.lt"class="anchor"></a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialOrd.html#method.lt"class="fnname">lt</a>(&self, other: <aclass="primitive"href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&</a>Rhs) -><aclass="primitive"href="https://doc.rust-lang.org/nightly/std/primitive.bool.html">bool</a></h4></section></summary><divclass='docblock'>This method tests less than (for <code>self</code> and <code>other</code>) and is used by the <code><</code> operator. <ahref="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialOrd.html#method.lt">Read more</a></div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.le"class="method trait-impl has-srclink"><spanclass="rightside"><spanclass="since"title="Stable since Rust version 1.0.0">1.0.0</span> · <aclass="srclink"href="https://doc.rust-lang.org/nightly/src/core/cmp.rs.html#1138">source</a></span><ahref="#method.le"class="anchor"></a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialOrd.html#method.le"class="fnname">le</a>(&self, other: <aclass="primitive"href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&</a>Rhs) -><aclass="primitive"href="https://doc.rust-lang.org/nightly/std/primitive.bool.html">bool</a></h4></section></summary><divclass='docblock'>This method tests less than or equal to (for <code>self</code> and <code>other</code>) and is
operator. <ahref="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialOrd.html#method.le">Read more</a></div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.gt"class="method trait-impl has-srclink"><spanclass="rightside"><spanclass="since"title="Stable since Rust version 1.0.0">1.0.0</span> · <aclass="srclink"href="https://doc.rust-lang.org/nightly/src/core/cmp.rs.html#1156">source</a></span><ahref="#method.gt"class="anchor"></a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialOrd.html#method.gt"class="fnname">gt</a>(&self, other: <aclass="primitive"href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&</a>Rhs) -><aclass="primitive"href="https://doc.rust-lang.org/nightly/std/primitive.bool.html">bool</a></h4></section></summary><divclass='docblock'>This method tests greater than (for <code>self</code> and <code>other</code>) and is used by the <code>></code> operator. <ahref="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialOrd.html#method.gt">Read more</a></div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.ge"class="method trait-impl has-srclink"><spanclass="rightside"><spanclass="since"title="Stable since Rust version 1.0.0">1.0.0</span> · <aclass="srclink"href="https://doc.rust-lang.org/nightly/src/core/cmp.rs.html#1175">source</a></span><ahref="#method.ge"class="anchor"></a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialOrd.html#method.ge"class="fnname">ge</a>(&self, other: <aclass="primitive"href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&</a>Rhs) -><aclass="primitive"href="https://doc.rust-lang.org/nightly/std/primitive.bool.html">bool</a></h4></section></summary><divclass='docblock'>This method tests greater than or equal to (for <code>self</code> and <code>other</code>) and is used by the <code>>=</code>
operator. <ahref="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialOrd.html#method.ge">Read more</a></div></details></div></details><detailsclass="rustdoc-toggle implementors-toggle"open><summary><sectionid="impl-TryIntoHeaderValue-for-Bearer"class="impl has-srclink"><aclass="srclink rightside"href="../../../../src/actix_web_httpauth/headers/www_authenticate/challenge/bearer/challenge.rs.html#135-141">source</a><ahref="#impl-TryIntoHeaderValue-for-Bearer"class="anchor"></a><h3class="code-header">impl TryIntoHeaderValue for <aclass="struct"href="struct.Bearer.html"title="struct actix_web_httpauth::headers::www_authenticate::bearer::Bearer">Bearer</a></h3></section></summary><divclass="impl-items"><detailsclass="rustdoc-toggle"open><summary><sectionid="associatedtype.Error"class="associatedtype trait-impl has-srclink"><ahref="#associatedtype.Error"class="anchor"></a><h4class="code-header">type <aclass="associatedtype">Error</a> = <aclass="struct"href="https://docs.rs/http/0.2.8/http/header/value/struct.InvalidHeaderValue.html"title="struct http::header::value::InvalidHeaderValue">InvalidHeaderValue</a></h4></section></summary><divclass='docblock'>The type returned in the event of a conversion error.</div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.try_into_value"class="method trait-impl has-srclink"><aclass="srclink rightside"href="../../../../src/actix_web_httpauth/headers/www_authenticate/challenge/bearer/challenge.rs.html#138-140">source</a><ahref="#method.try_into_value"class="anchor"></a><h4class="code-header">fn <aclass="fnname">try_into_value</a>(self) -><aclass="enum"href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html"title="enum core::result::Result">Result</a><<aclass="struct"href="https://docs.rs/http/0.2.8/http/header/value/struct.HeaderValue.html"title="struct http::header::value::HeaderValue">HeaderValue</a>, Self::Error></h4></section></summary><divclass='docblock'>Try to convert value to a HeaderValue.</div></details></div></details><sectionid="impl-Eq-for-Bearer"class="impl has-srclink"><aclass="srclink rightside"href="../../../../src/actix_web_httpauth/headers/www_authenticate/challenge/bearer/challenge.rs.html#38">source</a><ahref="#impl-Eq-for-Bearer"class="anchor"></a><h3class="code-header">impl <aclass="trait"href="https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html"title="trait core::cmp::Eq">Eq</a> for <aclass="struct"href="struct.Bearer.html"title="struct actix_web_httpauth::headers::www_authenticate::bearer::Bearer">Bearer</a></h3></section><sectionid="impl-StructuralEq-for-Bearer"class="impl has-srclink"><aclass="srclink rightside"href="../../../../src/actix_web_httpauth/headers/www_authenticate/challenge/bearer/challenge.rs.html#38">source</a><ahref="#impl-StructuralEq-for-Bearer"class="anchor"></a><h3class="code-header">impl <aclass="trait"href="https://doc.rust-lang.org/nightly/core/marker/trait.StructuralEq.html"title="trait core::marker::StructuralEq">StructuralEq</a> for <aclass="struct"href="struct.Bearer.html"title="struct actix_web_httpauth::headers::www_authenticate::bearer::Bearer">Bearer</a></h3></section><sectionid="impl-StructuralPartialEq-for-Bearer"class="impl has-srclink"><aclass="srclink rightside"href="../../../../src/actix_web_httpauth/headers/www_authenticate/challenge/bearer/challenge.rs.html#38">source</a><ahref="#impl-StructuralPartialEq-for-Bearer"class="anchor"></a><h3class="code-header">impl <aclass="trait"href="https://doc.rust-lang.org/nightly/core/marker/trait.StructuralPartialEq.html"title="trait core::marker::StructuralPartialEq">StructuralPartialEq</a> for <aclass="struct"href="struct.Bearer.html"title="struct actix_web_httpauth::headers::www_authenticate::bearer::Bearer">Bearer</a></h3></section></div><h2id="synthetic-implementations"class="small-section-header">Auto Trait Implementations<ahref="#synthetic-implementations"class="anchor"></a></h2><divid="synthetic-implementations-list"><sectionid
</div></details></div></details><detailsclass="rustdoc-toggle implementors-toggle"><summary><sectionid="impl-Instrument-for-Bearer"class="impl has-srclink"><aclass="srclink rightside"href="https://docs.rs/tracing/0.1.37/src/tracing/instrument.rs.html#276">source</a><ahref="#impl-Instrument-for-Bearer"class="anchor"></a><h3class="code-header">impl<T><aclass="trait"href="https://docs.rs/tracing/0.1.37/tracing/instrument/trait.Instrument.html"title="trait tracing::instrument::Instrument">Instrument</a> for T</h3></section></summary><divclass="impl-items"><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.instrument"class="method trait-impl has-srclink"><aclass="srclink rightside"href="https://docs.rs/tracing/0.1.37/src/tracing/instrument.rs.html#82">source</a><ahref="#method.instrument"class="anchor"></a><h4class="code-header">fn <ahref="https://docs.rs/tracing/0.1.37/tracing/instrument/trait.Instrument.html#method.instrument"class="fnname">instrument</a>(self, span: <aclass="struct"href="https://docs.rs/tracing/0.1.37/tracing/span/struct.Span.html"title="struct tracing::span::Span">Span</a>) -><aclass="struct"href="https://docs.rs/tracing/0.1.37/tracing/instrument/struct.Instrumented.html"title="struct tracing::instrument::Instrumented">Instrumented</a><Self></h4></section></summary><divclass='docblock'>Instruments this type with the provided <ahref="https://docs.rs/tracing/0.1.37/tracing/span/struct.Span.html"title="Span"><code>Span</code></a>, returning an
<code>Instrumented</code> wrapper. <ahref="https://docs.rs/tracing/0.1.37/tracing/instrument/trait.Instrument.html#method.instrument">Read more</a></div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.in_current_span"class="method trait-impl has-srclink"><aclass="srclink rightside"href="https://docs.rs/tracing/0.1.37/src/tracing/instrument.rs.html#121">source</a><ahref="#method.in_current_span"class="anchor"></a><h4class="code-header">fn <ahref="https://docs.rs/tracing/0.1.37/tracing/instrument/trait.Instrument.html#method.in_current_span"class="fnname">in_current_span</a>(self) -><aclass="struct"href="https://docs.rs/tracing/0.1.37/tracing/instrument/struct.Instrumented.html"title="struct tracing::instrument::Instrumented">Instrumented</a><Self></h4></section></summary><divclass='docblock'>Instruments this type with the <ahref="https://docs.rs/tracing/0.1.37/tracing/span/struct.Span.html#method.current">current</a><ahref="https://docs.rs/tracing/0.1.37/tracing/span/struct.Span.html"><code>Span</code></a>, returning an
<ahref="https://docs.rs/tracing/0.1.37/tracing/instrument/struct.WithDispatch.html"title="WithDispatch"><code>WithDispatch</code></a> wrapper. <ahref="https://docs.rs/tracing/0.1.37/tracing/instrument/trait.WithSubscriber.html#method.with_subscriber">Read more</a></div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><sectionid="method.with_current_subscriber"class="method trait-impl has-srclink"><aclass="srclink rightside"href="https://docs.rs/tracing/0.1.37/src/tracing/instrument.rs.html#221">source</a><ahref="#method.with_current_subscriber"class="anchor"></a><h4class="code-header">fn <ahref="https://docs.rs/tracing/0.1.37/tracing/instrument/trait.WithSubscriber.html#method.with_current_subscriber"class="fnname">with_current_subscriber</a>(self) -><aclass="struct"href="https://docs.rs/tracing/0.1.37/tracing/instrument/struct.WithDispatch.html"title="struct tracing::instrument::WithDispatch">WithDispatch</a><Self></h4></section></summary><divclass='docblock'>Attaches the current <ahref="https://docs.rs/tracing/0.1.37/tracing/dispatcher/index.html#setting-the-default-subscriber">default</a><ahref="https://docs.rs/tracing-core/0.1.22/tracing_core/subscriber/trait.Subscriber.html"><code>Subscriber</code></a> to this type, returning a