rust grpc

from article: https://dev.to/anshulgoyal15/a-beginners-guide-to-grpc-with-rust-3c7o

First run the server:

$ cargo run --bin server

Then run the client:

$ cargo run --bin client

Project Structure

  + proto/
       say.proto (defining messages and services)
  + src/
       client
       server
       hello
  build.rs
    -> will compile proto/say.proto file and saveit in an OUT_DIR
       and add an environment variable OUT_DIR which is available
       at build time so that we can use it later in our code.