if (buf == nullptr) {
    return tensorflow::errors::ResourceExhausted(
        "Failed to allocate memory to serialize message of type '",
        in.GetTypeName(), "' and size ", proto_size);
  }
  if (!in.SerializeWithCachedSizesToArray(static_cast<uint8_t*>(buf))) {
    port::Free(buf);
    return errors::InvalidArgument(
        "Unable to serialize ", in.GetTypeName(),
        " protocol buffer, perhaps the serialized size (", proto_size,