feat(gossipsub): feature gate metrics related code

Cargo.toml

@@ -80,7 +80,7 @@ libp2p-core = { version = "0.43.0", path = "core" }
 libp2p-dcutr = { version = "0.13.0", path = "protocols/dcutr" }
 libp2p-dns = { version = "0.43.0", path = "transports/dns" }
 libp2p-floodsub = { version = "0.46.1", path = "protocols/floodsub" }
-libp2p-gossipsub = { version = "0.48.1", path = "protocols/gossipsub" }
+libp2p-gossipsub = { version = "0.49.0", path = "protocols/gossipsub" }
 libp2p-identify = { version = "0.46.0", path = "protocols/identify" }
 libp2p-identity = { version = "0.2.10" }
 libp2p-kad = { version = "0.47.0", path = "protocols/kad" }

protocols/gossipsub/CHANGELOG.md

@@ -1,7 +1,13 @@
+## 0.49.0
+
+- Make `prometheus-client` an optional dependency with feature `metrics`. 
+  See [PR 5711](https://github.com/libp2p/rust-libp2p/pull/5711).
+
 ## 0.48.1
 - Improve `max_messages_per_rpc` consistency by ensuring RPC control messages also adhere to the existing limits.
   See [PR 5826](https://github.com/libp2p/rust-libp2p/pull/5826)
 
+
 ## 0.48.0
 
 - Allow broadcasting `IDONTWANT` messages when publishing to avoid downloading data that is already available.

protocols/gossipsub/Cargo.toml

@@ -3,7 +3,7 @@ name = "libp2p-gossipsub"
 edition = "2021"
 rust-version = { workspace = true }
 description = "Gossipsub protocol for libp2p"
-version = "0.48.1"
+version = "0.49.0"
 authors = ["Age Manning <[email protected]>"]
 license = "MIT"
 repository = "https://github.com/libp2p/rust-libp2p"
@@ -12,6 +12,7 @@ categories = ["network-programming", "asynchronous"]
 
 [features]
 wasm-bindgen = ["getrandom/js", "futures-timer/wasm-bindgen"]
+metrics = ["prometheus-client"]
 
 [dependencies]
 async-channel = "2.3.1"
@@ -39,7 +40,7 @@ sha2 = "0.10.8"
 tracing = { workspace = true }
 
 # Metrics dependencies
-prometheus-client = { workspace = true }
+prometheus-client = { workspace = true, optional = true }
 
 [dev-dependencies]
 libp2p-core = { workspace = true }