@Override
    @Deprecated
    public GrpcClientBuilder rpcPreprocessor(RpcPreprocessor decorator) {
        throw new UnsupportedOperationException("rpcPreprocessor() does not support gRPC. " +
                                                "Use preprocessor() instead.");
    }
Returns a newly-created gRPC client which implements the specified {@code clientType}, based on the
properties of this builder.
grpc/src/main/java/com/linecorp/armeria/client/grpc/GrpcClientBuilder.java