Add SSE polling support (SEP-1699) #3654

Job	Run time
checks / pre-commit	26s
checks / readme-snippets	13s
checks / test (3.10, lowest-direct, ubuntu-latest)	41s
checks / test (3.10, lowest-direct, windows-latest)	1m 57s
checks / test (3.11, lowest-direct, windows-latest)	2m 26s
checks / test (3.10, highest, ubuntu-latest)	37s
checks / test (3.11, lowest-direct, ubuntu-latest)	39s
checks / test (3.10, highest, windows-latest)	2m 11s
checks / test (3.11, highest, windows-latest)	2m 18s
checks / test (3.11, highest, ubuntu-latest)	42s
checks / test (3.13, lowest-direct, windows-latest)	2m 42s
checks / test (3.12, highest, ubuntu-latest)	47s
checks / test (3.12, highest, windows-latest)	3m 16s
checks / test (3.13, lowest-direct, ubuntu-latest)	42s
checks / test (3.12, lowest-direct, ubuntu-latest)	43s
checks / test (3.13, highest, ubuntu-latest)	42s
checks / test (3.13, highest, windows-latest)	2m 14s
checks / test (3.12, lowest-direct, windows-latest)	3m 11s
	26m 27s

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