_imageryConfigurationsModified() {
    const model = this._model;
    const imageryLayers = model.imageryLayers;
    const imageryConfigurations = this._imageryConfigurations;
    if (imageryLayers.length !== imageryConfigurations.length) {
      return true;
    }
    for (let i = 0; i < imageryLayers.length; i++) {
      const imageryLayer = imageryLayers.get(i);
      const imageryConfiguration = imageryConfigurations[i];

      if (imageryLayer.alpha !== imageryConfiguration.alpha) {
        return true;
      }
      if (imageryLayer.brightness !== imageryConfiguration.brightness) {
        return true;
      }
      if (imageryLayer.contrast !== imageryConfiguration.contrast) {
        return true;
      }
      if (imageryLayer.hue !== imageryConfiguration.hue) {
        return true;
      }
      if (imageryLayer.saturation !== imageryConfiguration.saturation) {
        return true;
      }
      if (imageryLayer.gamma !== imageryConfiguration.gamma) {
        return true;
      }
      if (imageryLayer.colorToAlpha !== imageryConfiguration.colorToAlpha) {
        return true;
      }
    }
    return false;
  }
Returns whether any setting of an imagery layer (like alpha or hue) has
been changed since the last time the <code>ImageryConfiguration</code>
objects have been updated.

@returns {boolean} Whether there was a modification