Tweak dependencies for wasm32 compilation.

For wasm32 we need to enable unstable features to
make `task::Builder::local` available.

client/network/Cargo.toml

@@ -16,7 +16,6 @@ targets = ["x86_64-unknown-linux-gnu"]
 prost-build = "0.6.1"
 
 [dependencies]
-async-std = "1.6.2"
 bitflags = "1.2.0"
 bs58 = "0.3.1"
 bytes = "0.5.0"
@@ -27,7 +26,7 @@ erased-serde = "0.3.9"
 fnv = "1.0.6"
 fork-tree = { version = "2.0.0-rc5", path = "../../utils/fork-tree" }
 futures = "0.3.4"
-futures-timer = "3.0.1"
+futures-timer = "3.0.2"
 futures_codec = "0.4.0"
 hex = "0.4.0"
 ip_network = "0.3.4"
@@ -61,6 +60,12 @@ void = "1.0.2"
 wasm-timer = "0.2"
 zeroize = "1.0.0"
 
+[target.'cfg(target_arch="wasm32")'.dependencies]
+async-std = { version = "1.6.2", features = ["futures-timer", "unstable"] }
+
+[target.'cfg(not(target_arch="wasm32"))'.dependencies]
+async-std = { version = "1.6.2", features = ["futures-timer"] }
+
 [dependencies.libp2p]
 version = "0.23.0"
 default-features = false

client/network/src/transport.rs

@@ -243,12 +243,25 @@ impl BandwidthMonitor {
 			output: monitor.clone(),
 		};
 
-		let _handle = task::Builder::new()
+		Self::spawn(task);
+
+		monitor
+	}
+
+	#[cfg(not(target_arch = "wasm32"))]
+	fn spawn(task: BandwidthTask) {
+		task::Builder::new()
 			.name("network-bandwidth".to_string())
 			.spawn(task.run())
 			.expect("Failed to spawn network-bandwidth task.");
+	}
 
-		monitor
+	#[cfg(target_arch = "wasm32")]
+	fn spawn(task: BandwidthTask) {
+		task::Builder::new()
+			.name("network-bandwidth".to_string())
+			.local(task.run())
+			.expect("Failed to spawn network-bandwidth task.");
 	}
 }