Parent context not passing to GRPC

[fir1]

There are 2 microservices, each of them starts its own "Span", however, the context of the parent "span" is not passed to the child both microservices are connected through gRPC.

I think the struct type which is linked to the context, should be converted to "metadata" in gRPC, then actual metadata will be attached to the context. Could you please confirm or perhaps you have some examples where you got it working with gRPC.
Thank you for your support.