add net_version call

CHANGELOG.md

@@ -21,6 +21,7 @@
 - add a method on the `Middleware` to broadcast a tx with a series of escalating gas prices via [#566](https://github.com/gakonst/ethers-rs/pull/566)
 - Remove unnecessary `Serialize` constraint to `R` (the Response type) in the `request` method of `JsonRpcClient`.
 - Fix `http Provider` data race when generating new request `id`s.
+- Add support for `net_version` RPC method. [595](https://github.com/gakonst/ethers-rs/pull/595)
 
 ### 0.5.3
 

ethers-providers/src/lib.rs

@@ -390,6 +390,10 @@ pub trait Middleware: Sync + Send + Debug {
         self.inner().get_chainid().await.map_err(FromErr::from)
     }
 
+    async fn get_net_version(&self) -> Result<U64, Self::Error> {
+        self.inner().get_net_version().await.map_err(FromErr::from)
+    }
+
     async fn get_balance<T: Into<NameOrAddress> + Send + Sync>(
         &self,
         from: T,

ethers-providers/src/provider.rs

@@ -432,6 +432,11 @@ impl<P: JsonRpcClient> Middleware for Provider<P> {
         self.request("eth_chainId", ()).await
     }
 
+    /// Returns the network version.
+    async fn get_net_version(&self) -> Result<U64, ProviderError> {
+        self.request("net_version", ()).await
+    }
+
     ////// Contract Execution
     //
     // These are relatively low-level calls. The Contracts API should usually be used instead.