fix(gossipsub): fixed incorrect default values in ConfigBuilder

protocols/gossipsub/CHANGELOG.md

@@ -8,6 +8,9 @@
 - Fix `unsubscribe_backoff` expecting number of seconds instead of `Duration`
   See [PR 6124](https://github.com/libp2p/rust-libp2p/pull/6124)
 
+- Fix incorrect default values in ConfigBuilder
+  See [PR 6113](https://github.com/libp2p/rust-libp2p/pull/6113)
+
 ## 0.49.2
 
 - Relax `Behaviour::with_metrics` requirements, do not require DataTransform and TopicSubscriptionFilter to also impl Default

protocols/gossipsub/src/config.rs

@@ -761,13 +761,22 @@ impl ConfigBuilder {
         self
     }
 
-    /// The maximum byte size for each gossip (default is 2048 bytes).
+    /// The maximum byte size for each gossip (default is 65536 bytes).
+    ///
+    /// ```rust
+    /// use libp2p_gossipsub::ConfigBuilder;
+    /// let mut config = ConfigBuilder::default();
+    /// assert_eq!(config.build().unwrap().max_transmit_size(), 65536);
+    /// config.max_transmit_size(1 << 20);
+    /// assert_eq!(config.build().unwrap().max_transmit_size(), 1 << 20);
+    /// ```
     pub fn max_transmit_size(&mut self, max_transmit_size: usize) -> &mut Self {
         self.config.protocol.default_max_transmit_size = max_transmit_size;
         self
     }
 
-    /// The maximum byte size for each gossip for a given topic. (default is 2048 bytes).
+    /// The maximum byte size for each gossip for a given topic. (default is
+    /// [`Self::max_transmit_size`]).
     pub fn max_transmit_size_for_topic(
         &mut self,
         max_transmit_size: usize,