feat: add smol runtime support with TCP and QUIC transports

libp2p/Cargo.toml

@@ -80,6 +80,7 @@ serde = ["libp2p-core/serde", "libp2p-kad?/serde", "libp2p-gossipsub?/serde"]
 tcp = ["dep:libp2p-tcp"]
 tls = ["dep:libp2p-tls"]
 tokio = ["libp2p-swarm/tokio", "libp2p-mdns?/tokio", "libp2p-tcp?/tokio", "libp2p-dns?/tokio", "libp2p-quic?/tokio", "libp2p-upnp?/tokio"]
+smol = ["libp2p-swarm/smol", "libp2p-tcp?/smol", "libp2p-quic?/smol"]
 uds = ["dep:libp2p-uds"]
 wasm-bindgen = ["futures-timer/wasm-bindgen", "getrandom/js", "libp2p-swarm/wasm-bindgen", "libp2p-gossipsub?/wasm-bindgen"]
 webrtc-websys = ['dep:libp2p-webrtc-websys']

libp2p/src/builder/phase/provider.rs

@@ -15,6 +15,10 @@ pub enum NoProviderSpecified {}
 /// Represents the Tokio runtime environment.
 pub enum Tokio {}
 
+#[cfg(all(not(target_arch = "wasm32"), feature = "smol"))]
+/// Represents the Smol runtime environment.
+pub enum Smol {}
+
 #[cfg(feature = "wasm-bindgen")]
 /// Represents the WasmBindgen environment for WebAssembly.
 pub enum WasmBindgen {}
@@ -35,6 +39,18 @@ impl SwarmBuilder<NoProviderSpecified, ProviderPhase> {
         }
     }
 
+    /// Configures the SwarmBuilder to use the Smol runtime.
+    /// This method is only available when compiling for non-Wasm
+    /// targets with the `smol` feature enabled.
+    #[cfg(all(not(target_arch = "wasm32"), feature = "smol"))]
+    pub fn with_smol(self) -> SwarmBuilder<Smol, TcpPhase> {
+        SwarmBuilder {
+            keypair: self.keypair,
+            phantom: PhantomData,
+            phase: TcpPhase {},
+        }
+    }
+
     /// Configures the SwarmBuilder for WebAssembly using WasmBindgen.
     /// This method is available when the `wasm-bindgen` feature is enabled.
     #[cfg(feature = "wasm-bindgen")]