chore: Reorganize examples and interop crates (#180)

* chore: Reorganize examples and interop crates

* fix interop tests

examples/src/helloworld/server.rs

@@ -0,0 +1,41 @@
+use tonic::{transport::Server, Request, Response, Status};
+
+pub mod hello_world {
+    tonic::include_proto!("helloworld");
+}
+
+use hello_world::{
+    greeter_server::{Greeter, GreeterServer},
+    HelloReply, HelloRequest,
+};
+
+#[derive(Default)]
+pub struct MyGreeter {}
+
+#[tonic::async_trait]
+impl Greeter for MyGreeter {
+    async fn say_hello(
+        &self,
+        request: Request<HelloRequest>,
+    ) -> Result<Response<HelloReply>, Status> {
+        println!("Got a request: {:?}", request);
+
+        let reply = hello_world::HelloReply {
+            message: format!("Hello {}!", request.into_inner().name).into(),
+        };
+        Ok(Response::new(reply))
+    }
+}
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let addr = "[::1]:50051".parse().unwrap();
+    let greeter = MyGreeter::default();
+
+    Server::builder()
+        .add_service(GreeterServer::new(greeter))
+        .serve(addr)
+        .await?;
+
+    Ok(())
+}