Perf[MQB]: make independent item pools for channels #2309

Job	Run time
Docker [ubuntu]	21m 45s
Build [macosx_arm64]	14m 0s
Build deps [ubuntu]	8s
Documentation	16s
Shellcheck	8s
Build [ubuntu]	16m 19s
UT [c++]	23m 17s
Fuzz test [identity]	1m 25s
Fuzz test [open_queue]	7m 50s
Fuzz test [configure_queue_stream]	4m 31s
IT [single/legacy_mode]	3m 29s
Build Prometheus plugin [ubuntu]	9m 46s
UT [python]	24s
Fuzz test [put]	2m 37s
IT [multi/legacy_mode]	16m 51s
Fuzz test [confirm]	3m 37s
IT [single/fsm_mode]	3m 7s
Fuzz test [close_queue]	17m 16s
Fuzz test [disconnect]	1m 49s
IT [multi/fsm_mode]	11m 33s
	2h 40m 8s

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