Detect the end of a batch pre-translate operation in a Translation Provider

I am working on a translation provider plugin for a client who wants to send all translation units over to their MT engine at once.  Does anyone know of a way to detect the end of a batch pre-translate operation in a Translation Provider?

Initial testing seems to show that Studio calls SearchTranslationUnitsMasked() in groups of ten TranslationUnit objects.  My goal is to store all of these in a data structure, send them all over at once to the server, and then populate the results accordingly.

For this I need to know 2 things: 1) whether the lookup is a batch mode (I've posted another question on this), and 2) when the end of the batch process has been reached.

Any help is appreciated.

Thanks,

Patrick