forwardClientToServer method may lose the response header when got rpc error?

[LugiaChang]

func (s *handler) forwardClientToServer(src grpc.ClientStream, dst grpc.ServerStream) chan error {
	ret := make(chan error, 1)
	go func() {
		f := &emptypb.Empty{}
		for i := 0; ; i++ {
			if err := src.RecvMsg(f); err != nil {
				ret <- err // this can be io.EOF which is happy case
				break
			}
			if i == 0 {
				// This is a bit of a hack, but client to server headers are only readable after first client msg is
				// received but must be written to server stream before the first msg is flushed.
				// This is the only place to do it nicely.
				md, err := src.Header()
				if err != nil {
					ret <- err
					break
				}
				if err := dst.SendHeader(md); err != nil {
					ret <- err
					break
				}
			}
			if err := dst.SendMsg(f); err != nil {
				ret <- err
				break
			}
		}
	}()
	return ret
}

Is the response header information lost when a remote RPC returns an error here? I found that this is indeed the case during my testing. Can the following logic be added? But I am not sure if src.Header is blocked under any circumstances.

func (s *handler) forwardClientToServer(src grpc.ClientStream, dst grpc.ServerStream) chan error {
	ret := make(chan error, 1)
	go func() {
		f := &emptypb.Empty{}
		for i := 0; ; i++ {
			if err := src.RecvMsg(f); err != nil {
				// set response header
				if i == 0 {
					md, err := src.Header()
					if err != nil {
						ret <- err
						break
					}
					if err := dst.SetHeader(md); err != nil {
						ret <- err
						break
					}
				}
				ret <- err // this can be io.EOF which is happy case
				break
			}
			if i == 0 {
				// This is a bit of a hack, but client to server headers are only readable after first client msg is
				// received but must be written to server stream before the first msg is flushed.
				// This is the only place to do it nicely.
				md, err := src.Header()
				if err != nil {
					ret <- err
					break
				}
				if err := dst.SendHeader(md); err != nil {
					ret <- err
					break
				}
			}
			if err := dst.SendMsg(f); err != nil {
				ret <- err
				break
			}
		}
	}()
	return ret
}