initializeMap_() {
    const paramHash = JSON.stringify(this.config_);
    if (this.templateCache_[paramHash]) {
      this.applyTemplate_(this.templateCache_[paramHash]);
      return;
    }
    let mapUrl = 'https://' + this.account_ + '.carto.com/api/v1/map';

    if (this.mapId_) {
      mapUrl += '/named/' + this.mapId_;
    }

    const client = new XMLHttpRequest();
    client.addEventListener(
      'load',
      this.handleInitResponse_.bind(this, paramHash),
    );
    client.addEventListener('error', this.handleInitError_.bind(this));
    client.open('POST', mapUrl);
    client.setRequestHeader('Content-type', 'application/json');
    client.send(JSON.stringify(this.config_));
  }
Issue a request to initialize the CartoDB map.
@private