Are all tiles guaranteed to be saved to Elastic?

It seems that the buffer is only written if it reaches a certain size but what if there is not enough data to reach the expected size, e.g. at the end of the data file?

Here is the check for buffer size that controls when data should be written to Elastic:
https://github.com/hms-dbmi/clodius/blob/develop/clodius/save_tiles.py#L124