private @NotNull Map<String, NullableLazyValue<XmlNSDescriptor>> getNSDescriptorMap() {
    XmlTag tag = myTag;
    return CachedValuesManager.getCachedValue(tag, () ->
      Result.create(computeNsDescriptorMap(tag),
                    PsiModificationTracker.MODIFICATION_COUNT, externalResourceModificationTracker(tag)));
  }
private @NotNull Map<String, NullableLazyValue<XmlNSDescriptor>> getNSDescriptorMap()