Support for PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION

[Bec-k]

In our code, we use os.environ["PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION"] = "python" Because of this, float arrays sent with grpcurl are converted into double, i could be wrong on this. In any case, adding this extra casting code is solving that, but still, it would be better if we could provide additional option to how grpcurl would handle casting implementation.

    arr = np.array(request.user_ids)
    user_ids = arr.astype(np.float)

[Bec-k]

As we use grpcurl for debugging purpose, we have to add that extra casting lines into our grpc handlers, because in production we don't need extra casting.