An example that demonstrates how to use the protobuf and protobuf_codegen crates together.
The source of the latest version of this example can be read here.
The protoc binary that you use to generate code needs to have a version that exactly matches the version of the protobuf crate you are using. More specifically, if you are using Rust protobuf x.y.z then you need to use protoc y.z. See here for more details on our versioning scheme.
The easiest way to get ahold of protoc is to download a prebuilt binary from the matching release here. Just make sure protoc is on your $PATH when you run cargo.