message: Add using id_type = ...
diff: @@ -47,6 +47,8 @@ class datagram_transport {
  public:
  // -- member types -----------------------------------------------------------
  + using id_type = ip_endpoint;
  +
  using buffer_type = std::vector<byte>;
  using buffer_cache_type = std::vector<buffer_type>;
  @@ -55,8 +57,7 @@ public:
  using transport_type = datagram_transport<Factory>;
  - using dispatcher_type = transport_worker_dispatcher<transport_type,
  - ip_endpoint>;
  + using dispatcher_type = transport_worker_dispatcher<transport_type, id_type>;
  using application_type = typename Factory::application_type;
  @@ -169,15 +170,15 @@ public:
  dispatcher_.timeout(*this, value, id);
  }
  - void set_timeout(uint64_t timeout_id, ip_endpoint ep) {
  - dispatcher_.set_timeout(timeout_id, ep);
  + void set_timeout(uint64_t timeout_id, id_type id) {
  + dispatcher_.set_timeout(timeout_id, id);
  }
  void handle_error(sec code) {
  dispatcher_.handle_error(code);
  }
  - error add_new_worker(node_id node, ip_endpoint id) {
  + error add_new_worker(node_id node, id_type id) {
  return dispatcher_.add_new_worker(*this, node, id);
  }
  @@ -214,13 +215,13 @@ public:
  prepare_next_read();
  }
  - void write_packet(ip_endpoint ep, span<buffer_type*> buffers) {
  + void write_packet(id_type id, span<buffer_type*> buffers) {
  CAF_ASSERT(!buffers.empty());
  if (packet_queue_.empty())
  manager().register_writing();
  // By convention, the first buffer is a header buffer. Every other buffer is
  // a payload buffer.
  - packet_queue_.emplace_back(ep, buffers);
  + packet_queue_.emplace_back(id, buffers);
  }
  // -- buffer management ------------------------------------------------------
  @@ -235,12 +236,11 @@ public:
  /// Helper struct for managing outgoing packets
  struct packet {
  - ip_endpoint destination;
  + id_type id;
  buffer_cache_type bytes;
  size_t size;
  - packet(ip_endpoint destination, span<buffer_type*> bufs)
  - : destination(destination) {
  + packet(id_type id, span<buffer_type*> bufs) : id(id) {
  size = 0;
  for (auto buf : bufs) {
  size += buf->size();
  @@ -286,7 +286,7 @@ private:
  std::vector<std::vector<byte>*> ptrs;
  for (auto& buf : packet.bytes)
  ptrs.emplace_back(&buf);
  - auto write_ret = write(handle_, make_span(ptrs), packet.destination);
  + auto write_ret = write(handle_, make_span(ptrs), packet.id);
  if (auto num_bytes = get_if<size_t>(&write_ret)) {
  CAF_LOG_DEBUG(CAF_ARG(handle_.id) << CAF_ARG(*num_bytes));
  CAF_LOG_WARNING_IF(*num_bytes < packet.size,
  