Fix the Sync issue. Details:

So the HTTP client future of Hyper is not Sync, thus the stream
that read blocks wasn't either. However Hyper's default Body type
requires a stream to be Sync for wrap_stream. Solution: reimplement
a custom HTTP body type.

src/rpc_client.rs

@@ -3,23 +3,25 @@ use std::sync::Arc;
 use std::time::Duration;
 
 use bytes::IntoBuf;
-use hyper::{Body, Method, Request, StatusCode};
-use hyper::client::Client;
 use futures::stream::futures_unordered::FuturesUnordered;
 use futures::stream::StreamExt;
+use futures_util::future::FutureExt;
+use hyper::client::Client;
+use hyper::{Body, Method, Request, StatusCode};
 
 use crate::data::*;
 use crate::error::Error;
-use crate::proto::Message;
 use crate::membership::System;
+use crate::proto::Message;
 
-pub async fn rpc_call_many(sys: Arc<System>,
-						   to: &[UUID],
-						   msg: &Message,
-						   timeout: Duration)
-	-> Vec<Result<Message, Error>>
-{
-	let mut resp_stream = to.iter()
+pub async fn rpc_call_many(
+	sys: Arc<System>,
+	to: &[UUID],
+	msg: &Message,
+	timeout: Duration,
+) -> Vec<Result<Message, Error>> {
+	let mut resp_stream = to
+		.iter()
 		.map(|to| rpc_call(sys.clone(), to, msg, timeout))
 		.collect::<FuturesUnordered<_>>();
 
@@ -30,14 +32,15 @@ pub async fn rpc_call_many(sys: Arc<System>,
 	results
 }
 
-pub async fn rpc_try_call_many(sys: Arc<System>,
-						       to: &[UUID],
-						       msg: &Message,
-						       stop_after: usize,
-						       timeout: Duration)
-	-> Result<Vec<Message>, Error>
-{
-	let mut resp_stream = to.iter()
+pub async fn rpc_try_call_many(
+	sys: Arc<System>,
+	to: &[UUID],
+	msg: &Message,
+	stop_after: usize,
+	timeout: Duration,
+) -> Result<Vec<Message>, Error> {
+	let mut resp_stream = to
+		.iter()
 		.map(|to| rpc_call(sys.clone(), to, msg, timeout))
 		.collect::<FuturesUnordered<_>>();
 
@@ -49,7 +52,7 @@ pub async fn rpc_try_call_many(sys: Arc<System>,
 			Ok(msg) => {
 				results.push(msg);
 				if results.len() >= stop_after {
-					break
+					break;
 				}
 			}
 			Err(e) => {
@@ -69,12 +72,12 @@ pub async fn rpc_try_call_many(sys: Arc<System>,
 	}
 }
 
-pub async fn rpc_call(sys: Arc<System>,
-					  to: &UUID,
-					  msg: &Message,
-					  timeout: Duration)
-	-> Result<Message, Error>
-{
+pub async fn rpc_call(
+	sys: Arc<System>,
+	to: &UUID,
+	msg: &Message,
+	timeout: Duration,
+) -> Result<Message, Error> {
 	let addr = {
 		let members = sys.members.read().await;
 		match members.status.get(to) {
@@ -91,24 +94,24 @@ pub struct RpcClient {
 
 impl RpcClient {
 	pub fn new() -> Self {
-		RpcClient{
+		RpcClient {
 			client: Client::new(),
 		}
 	}
 
-	pub async fn call(&self,
-					   to_addr: &SocketAddr,
-					   msg: &Message,
-					   timeout: Duration)
-		-> Result<Message, Error>
-	{
+	pub async fn call(
+		&self,
+		to_addr: &SocketAddr,
+		msg: &Message,
+		timeout: Duration,
+	) -> Result<Message, Error> {
 		let uri = format!("http://{}/rpc", to_addr);
 		let req = Request::builder()
 			.method(Method::POST)
 			.uri(uri)
 			.body(Body::from(rmp_to_vec_all_named(msg)?))?;
 
-		let resp_fut = self.client.request(req);
+		let resp_fut = self.client.request(req).fuse();
 		let resp = tokio::time::timeout(timeout, resp_fut).await??;
 
 		if resp.status() == StatusCode::OK {
@@ -116,7 +119,7 @@ impl RpcClient {
 			let msg = rmp_serde::decode::from_read::<_, Message>(body.into_buf())?;
 			match msg {
 				Message::Error(e) => Err(Error::RPCError(e)),
-				x => Ok(x)
+				x => Ok(x),
 			}
 		} else {
 			Err(Error::RPCError(format!("Status code {}", resp.status())))