<!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="A field value of an erased type."><title>Value in tracing::field - Rust</title><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../static.files/SourceSerif4-Regular-46f98efaafac5295.ttf.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../static.files/FiraSans-Regular-018c141bf0843ffd.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../static.files/FiraSans-Medium-8f9a781e4970d388.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../static.files/SourceCodePro-Regular-562dcc5011b6de7d.ttf.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../static.files/SourceCodePro-Semibold-d899c5a5c4aeb14a.ttf.woff2"><linkrel="stylesheet"href="../../static.files/normalize-76eba96aa4d2e634.css"><linkrel="stylesheet"href="../../static.files/rustdoc-5bc39a1768837dd0.css"><metaname="rustdoc-vars"data-root-path="../../"data-static-root-path="../../static.files/"data-current-crate="tracing"data-themes=""data-resource-suffix=""data-rustdoc-version="1.77.2 (25ef9e3d8 2024-04-09)"data-channel="1.77.2"data-search-js="search-dd67cee4cfa65049.js"data-settings-js="settings-4313503d2e1961c2.js"><scriptsrc="../../static.files/storage-4c98445ec4002617.js"></script><scriptdefersrc="sidebar-items.js"></script><scriptdefersrc="../../static.files/main-48f368f3872407c8.js"></script><noscript><linkrel="stylesheet"href="../../static.files/noscript-04d5337699b92874.css"></noscript><linkrel="alternate icon"type="image/png"href="../../static.files/favicon-16x16-8b506e7a72182f1c.png"><linkrel="alternate icon"type="image/png"href="../../static.files/favicon-32x32-422f7d1d52889060.png"><linkrel="icon"type="image/svg+xml"href="../../static.files/favicon-2c020d218678b618.svg"></head><bodyclass="rustdoc trait"><!--[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"title="show sidebar"></button><aclass="logo-container"href="../../tracing/index.html"><imgsrc="https://raw.githubusercontent.com/tokio-rs/tracing/master/assets/logo-type.png"alt=""></a></nav><navclass="sidebar"><divclass="sidebar-crate"><aclass="logo-container"href="../../tracing/index.html"><imgsrc="https://raw.githubusercontent.com/tokio-rs/tracing/master/assets/logo-type.png"alt="logo"></a><h2><ahref="../../tracing/index.html">tracing</a><spanclass="version">0.1.40</span></h2></div><h2class="location"><ahref="#">Value</a></h2><divclass="sidebar-elems"><section><h3><ahref="#required-methods">Required Methods</a></h3><ulclass="block"><li><ahref="#tymethod.record">record</a></li></ul><h3><ahref="#foreign-impls">Implementations on Foreign Types</a></h3><ulclass="block"><li><ahref="#impl-Value-for-%26T">&'a T</a></li><li><ahref="#impl-Value-for-%26mut+T">&'a mut T</a></li><li><ahref="#impl-Value-for-Arguments%3C'a%3E">Arguments<'a></a></li><li><ahref="#impl-Value-for-Box%3CT%3E">Box<T></a></li><li><ahref="#impl-Value-for-NonZero%3Ci128%3E">NonZero<i128></a></li><li><ahref="#impl-Value-for-NonZero%3Ci16%3E">NonZero<i16></a></li><li><ahref="#impl-Value-for-NonZero%3Ci32%3E">NonZero<i32></a></li><li><ahref="#impl-Value-for-NonZero%3Ci64%3E">NonZero<i64></a></li><li><ahref="#impl-Value-for-NonZero%3Ci8%3E">NonZero<i8></a></li><li><ahref="#impl-Value-for-NonZero%3Cisize%3E">NonZero<isize></a></li><li><ahref="#impl-Value-for-NonZero%3Cu128%3E">NonZero<u128></a></li><li><ahref="#impl-Value-for-NonZero%3Cu16%3E">NonZero<u16></a></li><li><ahref="#impl-Value-for-NonZero%3Cu32%3E">NonZero<u32></a></li><li><ahref="#impl-Value-for-NonZero%3Cu64%3E">NonZero<u64></a></li><li><ahref="#impl-Value-for-NonZe
<main><divclass="width-limiter"><navclass="sub"><formclass="search-form"><span></span><divid="sidebar-button"tabindex="-1"><ahref="../../tracing/all.html"title="show sidebar"></a></div><inputclass="search-input"name="search"aria-label="Run search in the documentation"autocomplete="off"spellcheck="false"placeholder="Click or press ‘S’ to search, ‘?’ for more options…"type="search"><divid="help-button"tabindex="-1"><ahref="../../help.html"title="help">?</a></div><divid="settings-menu"tabindex="-1"><ahref="../../settings.html"title="settings"><imgwidth="22"height="22"alt="Change settings"src="../../static.files/wheel-7b819b6101059cd0.svg"></a></div></form></nav><sectionid="main-content"class="content"><divclass="main-heading"><h1>Trait <ahref="../index.html">tracing</a>::<wbr><ahref="index.html">field</a>::<wbr><aclass="trait"href="#">Value</a><buttonid="copy-path"title="Copy item path to clipboard"><imgsrc="../../static.files/clipboard-7571035ce49a181d.svg"width="19"height="18"alt="Copy item path"></button></h1><spanclass="out-of-band"><aclass="src"href="../../src/tracing_core/field.rs.html#336">source</a> · <buttonid="toggle-all-docs"title="collapse all docs">[<span>−</span>]</button></span></div><preclass="rust item-decl"><code>pub trait Value: Sealed {
}</code></pre><detailsclass="toggle top-doc"open><summaryclass="hideme"><span>Expand description</span></summary><divclass="docblock"><p>A field value of an erased type.</p>
<p>Implementors of <code>Value</code> may call the appropriate typed recording methods on
the <ahref="trait.Visit.html"title="trait tracing::field::Visit">visitor</a> passed to their <code>record</code> method in order to indicate how
their data should be recorded.</p>
</div></details><h2id="required-methods"class="section-header">Required Methods<ahref="#required-methods"class="anchor">§</a></h2><divclass="methods"><detailsclass="toggle method-toggle"open><summary><sectionid="tymethod.record"class="method"><aclass="src rightside"href="../../src/tracing_core/field.rs.html#338">source</a><h4class="code-header">fn <ahref="#tymethod.record"class="fn">record</a>(&self, key: &<aclass="struct"href="struct.Field.html"title="struct tracing::field::Field">Field</a>, visitor: &mut dyn <aclass="trait"href="trait.Visit.html"title="trait tracing::field::Visit">Visit</a>)</h4></section></summary><divclass="docblock"><p>Visits this value with the given <code>Visitor</code>.</p>
</div></details></div><h2id="trait-implementations"class="section-header">Trait Implementations<ahref="#trait-implementations"class="anchor">§</a></h2><divid="trait-implementations-list"><detailsclass="toggle implementors-toggle"open><summary><sectionid="impl-Debug-for-dyn+Value"class="impl"><aclass="src rightside"href="../../src/tracing_core/field.rs.html#638">source</a><ahref="#impl-Debug-for-dyn+Value"class="anchor">§</a><h3class="code-header">impl <aclass="trait"href="https://doc.rust-lang.org/1.77.2/core/fmt/trait.Debug.html"title="trait core::fmt::Debug">Debug</a> for dyn <aclass="trait"href="../trait.Value.html"title="trait tracing::Value">Value</a></h3></section></summary><divclass="impl-items"><detailsclass="toggle method-toggle"open><summary><sectionid="method.fmt"class="method trait-impl"><aclass="src rightside"href="../../src/tracing_core/field.rs.html#639">source</a><ahref="#method.fmt"class="anchor">§</a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/1.77.2/core/fmt/trait.Debug.html#tymethod.fmt"class="fn">fmt</a>(&self, f: &mut <aclass="struct"href="https://doc.rust-lang.org/1.77.2/core/fmt/struct.Formatter.html"title="struct core::fmt::Formatter">Formatter</a><'_>) -><aclass="enum"href="https://doc.rust-lang.org/1.77.2/core/result/enum.Result.html"title="enum core::result::Result">Result</a><<aclass="primitive"href="https://doc.rust-lang.org/1.77.2/std/primitive.unit.html">()</a>, <aclass="struct"href="https://doc.rust-lang.org/1.77.2/core/fmt/struct.Error.html"title="struct core::fmt::Error">Error</a>></h4></section></summary><divclass='docblock'>Formats the value using the given formatter. <ahref="https://doc.rust-lang.org/1.77.2/core/fmt/trait.Debug.html#tymethod.fmt">Read more</a></div></details></div></details><detailsclass="toggle implementors-toggle"open><summary><sectionid="impl-Display-for-dyn+Value"class="impl"><aclass="src rightside"href="../../src/tracing_core/field.rs.html#667">source</a><ahref="#impl-Display-for-dyn+Value"class="anchor">§</a><h3class="code-header">impl <aclass="trait"href="https://doc.rust-lang.org/1.77.2/core/fmt/trait.Display.html"title="trait core::fmt::Display">Display</a> for dyn <aclass="trait"href="../trait.Value.html"title="trait tracing::Value">Value</a></h3></section></summary><divclass="impl-items"><detailsclass="toggle method-toggle"open><summary><sectionid="method.fmt-1"class="method trait-impl"><aclass="src rightside"href="../../src/tracing_core/field.rs.html#668">source</a><ahref="#method.fmt-1"class="anchor">§</a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/1.77.2/core/fmt/trait.Display.html#tymethod.fmt"class="fn">fmt</a>(&self, f: &mut <aclass="struct"href="https://doc.rust-lang.org/1.77.2/core/fmt/struct.Formatter.html"title="struct core::fmt::Formatter">Formatter</a><'_>) -><aclass="enum"href="https://doc.rust-lang.org/1.77.2/core/result/enum.Result.html"title="enum core::result::Result">Result</a><<aclass="primitive"href="https://doc.rust-lang.org/1.77.2/std/primitive.unit.html">()</a>, <aclass="struct"href="https://doc.rust-lang.org/1.77.2/core/fmt/struct.Error.html"title="struct core::fmt::Error">Error</a>></h4></section></summary><divclass='docblock'>Formats the value using the given formatter. <ahref="https://doc.rust-lang.org/1.77.2/core/fmt/trait.Display.html#tymethod.fmt">Read more</a></div></details></div></details></div><h2id="foreign-impls"class="section-header">Implementations on Foreign Types<ahref="#foreign-impls"class="anchor">§</a></h2><detailsclass="toggle implementors-toggle"><summary><sectionid="impl-Value-for-bool"class="impl"><aclass="src rightside"href="../../src/tracing_core/field.rs.html#517-526">source</a><ahref="#impl-Value-for-bool"class="anchor">§</a><h3class="code-header">impl <aclass="trait"href="../trait.Value.html"title="trait tracing::Value">Value</a> for <aclass="primitive"href="https://doc.rust-lang.org/1.77.2/std/primitive.bool.html">boo
