src/vs/editor/browser/services/abstractCodeEditorService.ts/AbstractCodeEditorService/setModelProperty
class AbstractCodeEditorService:	public setModelProperty(resource: URI, key: string, value: any): void {
		const key1 = resource.toString();
		let dest: Map<string, any>;
		if (this._modelProperties.has(key1)) {
			dest = this._modelProperties.get(key1)!;
		} else {
			dest = new Map<string, any>();
			this._modelProperties.set(key1, dest);
		}

		dest.set(key, value);
	}