change RwLock<Option<Arc>> to ArcSwapOption

Cargo.lock

@@ -129,6 +129,12 @@ version = "1.0.89"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "86fdf8605db99b54d3cd748a44c6d04df638eb5dafb219b135d0149bd0db01f6"
 
+[[package]]
+name = "arc-swap"
+version = "1.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "69f7f8c3906b62b754cd5326047894316021dcfe5a194c8ea52bdd94934a3457"
+
 [[package]]
 name = "assert_cfg"
 version = "0.1.0"
@@ -2604,6 +2610,7 @@ name = "librqbit"
 version = "7.1.0-beta.1"
 dependencies = [
  "anyhow",
+ "arc-swap",
  "async-backtrace",
  "async-stream",
  "async-trait",

crates/librqbit/Cargo.toml

@@ -110,6 +110,7 @@ async-trait = "0.1.81"
 async-backtrace = { version = "0.2", optional = true }
 notify = { version = "6.1.1", optional = true }
 walkdir = "2.5.0"
+arc-swap = "1.7.1"
 
 [build-dependencies]
 anyhow = "1"

crates/librqbit/src/limits.rs

@@ -1,6 +1,6 @@
+use arc_swap::ArcSwapOption;
 use governor::DefaultDirectRateLimiter as RateLimiter;
 use governor::Quota;
-use parking_lot::RwLock;
 use serde::Deserialize;
 use serde::Serialize;
 use std::num::NonZero;
@@ -13,7 +13,7 @@ pub struct LimitsConfig {
     pub download_bps: Option<NonZero<u32>>,
 }
 
-struct Limit(RwLock<Option<Arc<RateLimiter>>>);
+struct Limit(ArcSwapOption<RateLimiter>);
 
 impl Limit {
     fn new_inner(bps: Option<NonZero<u32>>) -> Option<Arc<RateLimiter>> {
@@ -22,11 +22,11 @@ impl Limit {
     }
 
     fn new(bps: Option<NonZero<u32>>) -> Self {
-        Self(RwLock::new(Self::new_inner(bps)))
+        Self(ArcSwapOption::new(Self::new_inner(bps)))
     }
 
     async fn acquire(&self, size: NonZero<u32>) -> anyhow::Result<()> {
-        let lim = self.0.read().clone();
+        let lim = self.0.load().clone();
         if let Some(rl) = lim.as_ref() {
             rl.until_n_ready(size).await?;
         }
@@ -35,7 +35,7 @@ impl Limit {
 
     fn set(&self, limit: Option<NonZero<u32>>) {
         let new = Self::new_inner(limit);
-        *self.0.write() = new;
+        self.0.swap(new);
     }
 }