From ef9ebaacdda254c9b3c85d36a47b09a502ac1a45 Mon Sep 17 00:00:00 2001
From: June Kim <kimjune01@gmail.com>
Date: Sat, 9 May 2026 10:12:28 -0700
Subject: [PATCH] feat(http2/client): expose reset_stream_duration option

Expose the h2 client builder's reset_stream_duration setting, which
controls how long reset stream state is kept in memory. This is useful
for tuning memory usage in connections that reset many streams.

Closes #2599 (partial)
---
 src/client/conn/http2.rs | 30 ++++++++++++++++++++++++++++++
 src/proto/h2/client.rs   |  5 +++++
 2 files changed, 35 insertions(+)

diff --git a/src/client/conn/http2.rs b/src/client/conn/http2.rs
index d62b4a4e99..f1bc4b1ecc 100644
--- a/src/client/conn/http2.rs
+++ b/src/client/conn/http2.rs
@@ -503,6 +503,36 @@ where
         self
     }
 
+    /// Sets the duration to remember locally reset streams.
+    ///
+    /// When a stream is explicitly reset by either the client or the server,
+    /// the HTTP/2 specification requires that any further frames received for
+    /// that stream must be ignored for "some time".
+    ///
+    /// In order to satisfy the specification, internal state must be maintained
+    /// to implement the behavior. This state grows linearly with the number of
+    /// streams that are locally reset.
+    ///
+    /// The `reset_stream_duration` setting configures the max amount of time
+    /// this state will be maintained in memory. Once the duration elapses, the
+    /// stream state is purged from memory.
+    ///
+    /// Once the stream has been fully purged from memory, any additional frames
+    /// received for that stream will result in a connection level protocol
+    /// error, forcing the connection to terminate.
+    ///
+    /// The default value is determined by the `h2` crate, and is currently
+    /// 1 second.
+    ///
+    /// See the documentation of [`h2::client::Builder::reset_stream_duration`] for more
+    /// details.
+    ///
+    /// [`h2::client::Builder::reset_stream_duration`]: https://docs.rs/h2/client/struct.Builder.html#method.reset_stream_duration
+    pub fn reset_stream_duration(&mut self, dur: Duration) -> &mut Self {
+        self.h2_builder.reset_stream_duration = Some(dur);
+        self
+    }
+
     /// Constructs a connection with the configured options and IO.
     /// See [`client::conn`](crate::client::conn) for more.
     ///
diff --git a/src/proto/h2/client.rs b/src/proto/h2/client.rs
index bf154e4580..51f548444e 100644
--- a/src/proto/h2/client.rs
+++ b/src/proto/h2/client.rs
@@ -77,6 +77,7 @@ pub(crate) struct Config {
     pub(crate) max_local_error_reset_streams: Option<usize>,
     pub(crate) header_table_size: Option<u32>,
     pub(crate) max_concurrent_streams: Option<u32>,
+    pub(crate) reset_stream_duration: Option<Duration>,
 }
 
 impl Default for Config {
@@ -97,6 +98,7 @@ impl Default for Config {
             max_local_error_reset_streams: Some(1024),
             header_table_size: None,
             max_concurrent_streams: None,
+            reset_stream_duration: None,
         }
     }
 }
@@ -126,6 +128,9 @@ fn new_builder(config: &Config) -> Builder {
     if let Some(max) = config.max_concurrent_streams {
         builder.max_concurrent_streams(max);
     }
+    if let Some(dur) = config.reset_stream_duration {
+        builder.reset_stream_duration(dur);
+    }
     builder
 }