there doesn't seem to be much point in passing this limit all around, since
both sides agree it's meant to be 100.

Figuring out how to correctly limit updates from this stream without dropping
entries is far more complicated than just counting the number of rows being
returned. We need to consider each query separately and, if any one query hits
the limit, truncate the results from the others.

I think this also fixes some potentially long-standing bugs where events or
state changes could get missed if we hit the limit on either query.