src/vs/platform/configuration/common/configurationService.ts/ConfigurationService/trigger
class ConfigurationService:	private trigger(configurationChange: IConfigurationChange, previous: IConfigurationData, source: ConfigurationTarget): void {
		const event = new ConfigurationChangeEvent(configurationChange, { data: previous }, this.configuration);
		event.source = source;
		event.sourceConfig = this.getTargetConfiguration(source);
		this._onDidChangeConfiguration.fire(event);
	}