在R中保存和增量更新最近邻居模型

There are several nearest neighbor R packages (e.g., FNN, RANN, yaImpute) but none of them seem to allow saving off the NN data structure (cover tree, KD tree etc.) so that the nearest neighbors of new queries can be calculated without reconstructing the whole tree. Are there any such functions in R?There are several nearest neighbor R packages (