Fix/providers (#590)

* ethers-providers: Fix http Provider request id data race

* ethers-providers: Remove Serialize from JsonRpcClient Response

* Update changelog

CHANGELOG.md

@@ -19,6 +19,8 @@
 - add the missing constructor for `Timelag` middleware via [#568](https://github.com/gakonst/ethers-rs/pull/568)
 - re-export error types for `Http` and `Ws` providers in [#570](https://github.com/gakonst/ethers-rs/pull/570)
 - 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.
 
 ### 0.5.3
 

ethers-providers/src/lib.rs

@@ -116,7 +116,7 @@ pub trait JsonRpcClient: Debug + Send + Sync {
     async fn request<T, R>(&self, method: &str, params: T) -> Result<R, Self::Error>
     where
         T: Debug + Serialize + Send + Sync,
-        R: Serialize + DeserializeOwned;
+        R: DeserializeOwned;
 }
 
 use ethers_core::types::*;

ethers-providers/src/transports/http.rs

@@ -68,8 +68,7 @@ impl JsonRpcClient for Provider {
         method: &str,
         params: T,
     ) -> Result<R, ClientError> {
-        let next_id = self.id.load(Ordering::SeqCst) + 1;
-        self.id.store(next_id, Ordering::SeqCst);
+        let next_id = self.id.fetch_add(1, Ordering::SeqCst);
 
         let payload = Request::new(next_id, method, params);