Example repo that shows an issue with Ruby <-> Elixir GRPC communication

How to reproduce the issue:

1. Start the Ruby server:

source

$ cd ruby_server
$ ruby app.rb

This will start a Hello World server on the 0.0.0.0:50051 host.

2. Execute a call with the Elixir client:

source

$ cd elixir_client
$ mix hello

With this example, I get the following output:

{:error,
 %GRPC.RPCError{message: "shouldn't finish when getting headers", status: 13}}
{:error,
 %GRPC.RPCError{message: "shouldn't finish when getting headers", status: 13}}
{:error,
 %GRPC.RPCError{message: "shouldn't finish when getting headers", status: 13}}
{:error,
 %GRPC.RPCError{message: "shouldn't finish when getting headers", status: 13}}
{:error,
 %GRPC.RPCError{message: "shouldn't finish when getting headers", status: 13}}
{:error,
 %GRPC.RPCError{message: "shouldn't finish when getting headers", status: 13}}
{:error,
 %GRPC.RPCError{message: "shouldn't finish when getting headers", status: 13}}

Additional clues

The issue seems to be related to timing of the response. If I remove the sleep 0.3 from the server implementation, everything seems to be working.