feat(pageserver): add k-merge layer iterator with lazy loading #23441

Job	Run time
check-permissions / check-permissions	1s
tag	11s
cancel-previous-e2e-tests	1s
check-build-tools-image / check-image	4s
build-build-tools-image / check-image / check-image	5s
trigger-custom-extensions-build-and-wait	5m 52s
build-build-tools-image / build-image	0s
build-build-tools-image / merge-images	0s
build-neon (debug)	14m 33s
build-neon (release)	13m 31s
check-codestyle-python	33s
check-codestyle-rust	17m 5s
neon-image-arch (x64)	6m 59s
compute-node-image-arch (v14, x64)	5m 4s
get-benchmarks-durations	0s
compute-node-image-arch (v14, arm64)	10m 30s
neon-image-arch (arm64)	12m 32s
compute-node-image-arch (v15, x64)	5m 53s
compute-node-image-arch (v15, arm64)	10m 4s
compute-node-image-arch (v16, x64)	5m 50s
compute-node-image-arch (v16, arm64)	10m 51s
compute-node-image (v14)	22s
compute-node-image (v15)	15s
compute-node-image (v16)	24s
vm-compute-node-image (v14)	1m 32s
vm-compute-node-image (v15)	1m 41s
vm-compute-node-image (v16)	1m 35s
neon-image	49s
test-images (x64)	10m 12s
test-images (arm64)	14m 4s
regress-tests (debug, v14)	23m 8s
regress-tests (debug, v15)	23m 3s
regress-tests (debug, v16)	22m 5s
regress-tests (release, v14)	12m 43s
benchmarks	0s
regress-tests (release, v15)	11m 45s
regress-tests (release, v16)	12m 20s
coverage-report (debug)	5m 22s
create-test-report	2m 10s
report-benchmarks-failures	0s
promote-images	46s
conclusion	1s
deploy	0s
pin-build-tools-image	0s
promote-compatibility-data	0s
trigger-e2e-tests / cancel-previous-e2e-tests	1s
trigger-e2e-tests / tag	12s
trigger-e2e-tests / trigger-e2e-tests	1m 8s
	4h 25m 17s

Provide feedback