Context: #66205 uncovered incorrect behavior around query progress data flushing. Currently, progress flush only occurs when there are new result blocks to return. For this output format (and for the other *WithProgress formats as well), progress should be flushed periodically even in the absence of new result blocks.

@alexey-milovidov - is there an open issue for the underlying problem with flushing progress? Should I open one?

Originally posted by @ArctypeZach in #69989 (comment)