add note on required dependencies (#15)

* add note on required dependencies

* Include build dependencies in codegen

tonic-examples/README.md

@@ -70,3 +70,4 @@ $ cargo run --bin tls-client
 
 ```bash
 $ cargo run --bin tls-server
+

tonic/Cargo.toml

@@ -23,8 +23,8 @@ categories = ["web-programming", "network-programming", "asynchronous"]
 keywords = ["rpc", "grpc", "async", "futures", "protobuf"]
 
 [features]
-default = ["transport", "codegen", "prost"]
+default = ["transport", "codegen"]
-codegen = ["async-trait"]
+codegen = ["async-trait", "prost", "prost-derive", "bytes"]
 transport = [
     "hyper",
     "tokio",
@@ -43,7 +43,6 @@ futures-util-preview = "=0.3.0-alpha.18"
 tracing = "0.1"
 http = "0.1.14"
 base64 = "0.10"
-bytes = "0.4.7"
 
 percent-encoding = "1.0.1"
 tower-service = "=0.3.0-alpha.1"
@@ -54,9 +53,11 @@ pin-project = "=0.4.0-alpha.11"
 
 # prost
 prost = { version = "0.5", optional = true }
+prost-derive = { version = "0.5", optional = true }
 
 # codegen
 async-trait = { version = "0.1.13", optional = true }
+bytes = {version = "0.4", optional = true}
 
 # transport
 hyper = { git = "https://github.com/hyperium/hyper", features = ["unstable-stream"], optional = true, rev = "2b0405c48c10bca7893c30ea960ac20a41a8578f" }

tonic/src/codegen.rs

@@ -34,3 +34,7 @@ impl std::fmt::Display for Never {
 }
 
 impl std::error::Error for Never {}
+
+pub use prost::*;
+pub use prost_derive::*;
+pub use bytes::*;