The protocol is stateless, just as HTTP is stateless¹. This means that every request is handled independently. Pagination is like “please give me page one for the query ‘foo’” followed by “please give me page two for the query ‘foo’”—so if you lost your connection in the middle, you’re fine. By contrast, IMAP is stateful, and pagination can be more like “I’m starting a query ‘foo’, please give me the results” followed by “please give me the next page”, with the result that a dropped connection can leave you stranded high and dry, having to do everything over again if it’s even possible to. (In practice, now-widely-adopted extensions have been developed to avoid this happening. And really this whole paragraph is a simplification of reality.)
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¹ Well, HTTP is stateless, but in the HTTP/2 and HTTP/3 wire formats, the HPACK and QPACK header compression schemes use connection-level state. But developers talk in terms of HTTP requests, not HTTP/2 or HTTP/3 frames, so it’s OK and HTTP is still stateless.
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¹ Well, HTTP is stateless, but in the HTTP/2 and HTTP/3 wire formats, the HPACK and QPACK header compression schemes use connection-level state. But developers talk in terms of HTTP requests, not HTTP/2 or HTTP/3 frames, so it’s OK and HTTP is still stateless.