pub fn file_descriptor_set_path(mut self, path: impl AsRef<Path>) -> Self {
        self.file_descriptor_set_path = Some(path.as_ref().to_path_buf());
        self
    }
Generate a file containing the encoded `prost_types::FileDescriptorSet` for protocol buffers
modules. This is required for implementing gRPC Server Reflection.
tonic-build/src/prost.rs