if we call mongo_cursor_next() for the first time and there is no result, we should return MONGO_CURSOR_EXHAUSTED

As far as I understand, it is possible to create my own cursor, with:
mongo_cursor_init()
mongo_cursor_set_query()
mongo_cursor_set_skip()
mongo_cursor_set_limit()
mongo_cursor_set_options()

In that case, to run for the first time the cursor, I use directly:
mongo_cursor_next()

But if the cursor returns no result, with this commit: 2bed7e5 I don't get anymore MONGO_CURSOR_EXHAUSTED in the cursor error.