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• Backward Incompatible Change

Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):

JSONEachRowWithProgress will write the progress whenever the progress happens. In previous versions, the progress was shown only after each block of the result, which made it useless. Change the way how the progress is displayed: it will not show zero values. Keep in mind that the progress is sent even if it happens frequently. It can generate a significant volume of traffic. Keep in mind that the progress is not flushed when the output is compressed. This closes #70800.

I've also discovered a few idiosyncracies in the implementation:

• result_rows and result_bytes are not updated at all;
• elapsed_ns is not updated either.

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