message: Fix event numbering
diff: @@ -241,7 +241,7 @@ void multiplexer::shutdown() {
  }
  close_pipe();
  } else {
  - write_to_pipe(5, nullptr);
  + write_to_pipe(4, nullptr);
  }
  }
  @@ -292,10 +292,10 @@ void multiplexer::del(ptrdiff_t index) {
  }
  void multiplexer::write_to_pipe(uint8_t opcode, const socket_manager_ptr& mgr) {
  - CAF_ASSERT(opcode == 0 || opcode == 1 || opcode == 4 || opcode == 5);
  + CAF_ASSERT(opcode == 0 || opcode == 1 || opcode == 4);
  CAF_ASSERT(mgr != nullptr || opcode == 4);
  pollset_updater::msg_buf buf;
  - if (opcode != 5)
  + if (opcode != 4)
  mgr->ref();
  buf[0] = static_cast<byte>(opcode);
  auto value = reinterpret_cast<intptr_t>(mgr.get());
  