message: Implement read retries for udp
diff: @@ -79,6 +79,8 @@ public:
  }
  bool handle_read_event(endpoint_manager&) override {
  + size_t reads = 0;
  + while (reads++ < this->max_consecutive_reads_) {
  CAF_LOG_TRACE(CAF_ARG(this->handle_.id));
  auto ret = read(this->handle_, this->read_buf_);
  if (auto res = get_if<std::pair<size_t, ip_endpoint>>(&ret)) {
  @@ -94,6 +96,7 @@ public:
  this->next_layer_.handle_error(err);
  return false;
  }
  + }
  return true;
  }
  