message: Check doorman ptr before dereferencing it
diff: @@ -744,8 +744,9 @@ bool test_multiplexer::try_accept_connection() {
  doormen.emplace_back(&kvp.second);
  }
  // Try accepting a new connection on all existing doorman.
  - return std::any_of(doormen.begin(), doormen.end(),
  - [](doorman_data* x) { return x->ptr->new_connection(); });
  + return std::any_of(doormen.begin(), doormen.end(), [](doorman_data* x) {
  + return x->ptr != nullptr ? x->ptr->new_connection() : false;
  + });
  }
  bool test_multiplexer::try_read_data() {
  