code: protected function connect(ConnectionInterface $connection)
      {
          $this->ldap->connect();
  
          $this->ldap->option(LDAP_OPT_PROTOCOL_VERSION, $connection::VERSION);
          $this->ldap->option(LDAP_OPT_REFERRALS, $connection::REFERRALS);
          $this->ldap->option(LDAP_OPT_TIMELIMIT, $connection::TIMELIMIT);
          $this->ldap->option(LDAP_OPT_NETWORK_TIMEOUT, $connection::TIMELIMIT);
  
          // For debug purposes only.
          // $this->ldap->option(LDAP_OPT_DEBUG_LEVEL, 7);
  
          $this->ldap->bind($this->admin_user, $this->admin_pass);
      }
docs: Initializes the connecting parameters.
  The actual connect happens with $this->ldap->bind()
  
  @param ConnectionInterface $connection
  
  @throws Exceptions\ConnectionException