Reexport/tokio serde (#332)

Re-export tokio_serde when the serde-transport feature is enabled.

example-service/Cargo.toml

@@ -19,8 +19,6 @@ futures = "0.3"
 serde = { version = "1.0" }
 tarpc = { version = "0.23", path = "../tarpc", features = ["full"] }
 tokio = { version = "0.3", features = ["full"] }
-tokio-serde = { version = "0.7.1", features = ["json"] }
-tokio-util = { version = "0.5", features = ["codec"] }
 
 [lib]
 name = "service"

example-service/src/client.rs

@@ -6,8 +6,7 @@
 
 use clap::{App, Arg};
 use std::{io, net::SocketAddr};
-use tarpc::{client, context};
-use tokio_serde::formats::Json;
+use tarpc::{client, context, tokio_serde::formats::Json};
 
 #[tokio::main]
 async fn main() -> io::Result<()> {

example-service/src/server.rs

@@ -14,8 +14,8 @@ use std::{
 use tarpc::{
     context,
     server::{self, Channel, Handler},
+    tokio_serde::formats::Json,
 };
-use tokio_serde::formats::Json;
 
 // This is the type that implements the generated World trait. It is the business logic
 // and is used to start the server.