src/vs/editor/common/model/textModel.ts/TextModel/changeDecorations
class TextModel:	public changeDecorations<T>(callback: (changeAccessor: model.IModelDecorationsChangeAccessor) => T, ownerId: number = 0): T | null {
		this._assertNotDisposed();

		try {
			this._onDidChangeDecorations.beginDeferredEmit();
			return this._changeDecorations(ownerId, callback);
		} finally {
			this._onDidChangeDecorations.endDeferredEmit();
		}
	}