From a0b7e85a40a7a8e7e22715f668582c1092899762 Mon Sep 17 00:00:00 2001
From: David Pedersen <david.pdrsn@gmail.com>
Date: Wed, 27 Jan 2021 23:01:26 +0100
Subject: [PATCH] Add comment explaining what `FormattedFields` is

---
 tracing-subscriber/src/fmt/format/mod.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tracing-subscriber/src/fmt/format/mod.rs b/tracing-subscriber/src/fmt/format/mod.rs
index 9b6cf85d63..b2761e991e 100644
--- a/tracing-subscriber/src/fmt/format/mod.rs
+++ b/tracing-subscriber/src/fmt/format/mod.rs
@@ -82,9 +82,13 @@ use fmt::{Debug, Display};
 ///             write!(writer, "{}", span.name())?;
 ///
 ///             let ext = span.extensions();
+///
+///             // `FormattedFields` is a a formatted representation of the span's
+///             // fields which are stored in its extensions
 ///             let fields = &ext
 ///                 .get::<FormattedFields<N>>()
 ///                 .expect("will never be `None`");
+///
 ///             if !fields.is_empty() {
 ///                 write!(writer, "{{{}}}", fields)?;
 ///             }