Bug: `quinn::connection::Connection::open_bi` will hang when reach `max_concurrent_bi_streams` limit

[finpluto]

Bug: 当同时开启的stream数到达quinn的max_concurrent_bi_streams（默认为100）上限后，调用quinn::connection::Connection::open_bi()将会挂起task，导致连接超时。

可以考虑的解决方案：

1. tuic_client::relay::connection::Connection::get_bi_stream()处通过Register的流计数实现自动扩容流上限
2. 加入可配置项允许用户设置max_concurrent_bi_streams值
3. 创建quic::connection::Connection时调用set_max_concurrent_bi_streams设置为更大值

---

Bug: quinn::connection::Connection::open_bi will hang when reach max_concurrent_bi_streams limit, cause relay task timeout.

possible solutions:

1. make tuic_client::relay::connection::Connection::get_bi_stream() call expand max_concurrent_bi_streams automatically;
2. add a configuration option to allow customizing the value of max_concurrent_bi_stream;
3. call set_max_concurrent_bi_streams with a number larger than 100 when creating quic::connection::Connection

---

refs:

• https://github.com/quinn-rs/quinn/issues/1231#issuecomment-1008331336

[finpluto]

connection完成超时（大于1分钟）的统计图表。 a connection finish time tracing diagram.

[finpluto]

临时补丁/workaround patch

client:

diff --git a/client/src/relay/connection.rs b/client/src/relay/connection.rs
index 1face7d..d4accc7 100644
--- a/client/src/relay/connection.rs
+++ b/client/src/relay/connection.rs
@@ -163,6 +163,9 @@ impl Connection {
             conn.await?
         };
 
+        connection.set_max_concurrent_bi_streams(65536u32.into());
+        connection.set_max_concurrent_uni_streams(65536u32.into());
+
         let conn = Self::new(connection, config).await;
         let uni_streams = IncomingUniStreams::new(uni_streams, conn.stream_reg.get_registry());
 

server:

diff --git a/server/src/connection/mod.rs b/server/src/connection/mod.rs
index a4c8ff0..b2904a2 100644
--- a/server/src/connection/mod.rs
+++ b/server/src/connection/mod.rs
@@ -59,6 +59,9 @@ impl Connection {
                 let is_closed = IsClosed::new();
                 let is_authed = IsAuthenticated::new(is_closed.clone());
 
+                connection.set_max_concurrent_uni_streams(65536u32.into());
+                connection.set_max_concurrent_bi_streams(65536u32.into());
+
                 let conn = Self {
                     controller: connection,
                     udp_packet_from: UdpPacketFrom::new(),

修改后会有比较大的内存占用。

may cause dramatic memory consumption.

[EAimTY]

最近正在重构，打算用思路 1 解决这个问题。

quinn 的文档中提到的 max_concurrent_uni_streams：

Modify the number of remotely initiated unidirectional streams that may be concurrently open

因此 max_concurrent_uni_streams 的数值应只会影响 streams initiated by peer。目前 TUIC 的 register 只针对 task 进行计数，没有区分 stream 流向，所以需要重构这一部分