@UnstableApi
    public static GrpcClientBuilder builder(HttpPreprocessor httpPreprocessor) {
        requireNonNull(httpPreprocessor, "httpPreprocessor");
        return builder(GrpcSerializationFormats.PROTO, httpPreprocessor);
    }
Returns a new {@link GrpcClientBuilder} that builds the client that is configured with
{@link HttpPreprocessor}.

<p>Note that {@link GrpcSerializationFormats#PROTO} will be used by default.
grpc/src/main/java/com/linecorp/armeria/client/grpc/GrpcClients.java