<main><divclass="width-limiter"><navclass="sub"><formclass="search-form"><span></span><divid="sidebar-button"tabindex="-1"><ahref="../../../tracing_subscriber/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>Function <ahref="../../index.html">tracing_subscriber</a>::<wbr><ahref="../index.html">fmt</a>::<wbr><ahref="index.html">format</a>::<wbr><aclass="fn"href="#">debug_fn</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_subscriber/fmt/format/mod.rs.html#284-289">source</a> · <buttonid="toggle-all-docs"title="collapse all docs">[<span>−</span>]</button></span></div><preclass="rust item-decl"><code>pub fn debug_fn<F>(f: F) -><aclass="struct"href="struct.FieldFn.html"title="struct tracing_subscriber::fmt::format::FieldFn">FieldFn</a><F><divclass="where">where