Play around with NonCopyable continuation

[fabianfett]

First draft for adopting NonCopyable continuations.

[github-actions]

❌ Benchmark comparison failed with error ❌

Summary

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Threshold deviations for ValkeyBenchmarks:Connection: Pipeline array benchmark
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Malloc (total) (K, %)	main	pull_request	Difference %	Threshold %
p25	18	23	26	5

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Threshold deviations for ValkeyBenchmarks:Connection: Pipeline benchmark
========================================================================

Malloc (total) (K, %)	main	pull_request	Difference %	Threshold %
p25	24	27	12	5
p50	24	28	12	5
p75	25	28	12	5

New baseline 'pull_request' is WORSE than the 'main' baseline thresholds.

Full Benchmark Comparison

Comparing results between 'main' and 'pull_request'

Host '686e481dcd5f' with 4 'x86_64' processors with 15 GB memory, running:
#17~24.04.1-Ubuntu SMP Mon Dec  1 20:10:50 UTC 2025

ValkeyBenchmarks

Client: GET benchmark metrics

Malloc (total): results within specified thresholds, fold down for details.

Malloc (total) *	p0	p25	p50	p75	p90	p99	p100	Samples
main	52	54	55	57	59	59	59	6
pull_request	51	52	55	56	56	56	56	6
Δ	-1	-2	0	-1	-3	-3	-3	0
Improvement %	2	4	0	2	5	5	5	0

Client: GET benchmark | parallel 20 | 20 concurrent connections metrics

Malloc (total): results within specified thresholds, fold down for details.

Malloc (total) *	p0	p25	p50	p75	p90	p99	p100	Samples
main	49	55	58	59	62	65	65	24
pull_request	52	54	56	58	60	61	61	26
Δ	3	-1	-2	-1	-2	-4	-4	2
Improvement %	-6	2	3	2	3	6	6	2

Connection: GET benchmark metrics

Malloc (total): results within specified thresholds, fold down for details.

Malloc (total) *	p0	p25	p50	p75	p90	p99	p100	Samples
main	4	4	4	4	4	4	4	7
pull_request	4	4	4	4	4	4	4	8
Δ	0	0	0	0	0	0	0	1
Improvement %	0	0	0	0	0	0	0	1

Connection: GET benchmark – NoOpTracer metrics

Malloc (total): results within specified thresholds, fold down for details.

Malloc (total) *	p0	p25	p50	p75	p90	p99	p100	Samples
main	4	7	8	9	9	9	9	8
pull_request	4	6	7	8	8	8	8	8
Δ	0	-1	-1	-1	-1	-1	-1	0
Improvement %	0	14	12	11	11	11	11	0

Connection: Pipeline array benchmark metrics

Malloc (total): results within specified thresholds, fold down for details.

Malloc (total) *	p0	p25	p50	p75	p90	p99	p100	Samples
main	14	18	25	29	29	29	29	7
pull_request	9	23	24	24	25	25	25	7
Δ	-5	5	-1	-5	-4	-4	-4	0
Improvement %	36	-28	4	17	14	14	14	0

Connection: Pipeline benchmark metrics

Malloc (total): results within specified thresholds, fold down for details.

Malloc (total) *	p0	p25	p50	p75	p90	p99	p100	Samples
main	7	24	24	25	25	25	25	7
pull_request	7	27	28	28	28	28	28	7
Δ	0	3	4	3	3	3	3	0
Improvement %	0	-12	-17	-12	-12	-12	-12	0

HashSlot – {user}.whatever metrics

Malloc (total): results within specified thresholds, fold down for details.

Malloc (total) *	p0	p25	p50	p75	p90	p99	p100	Samples
main	0	0	0	0	0	0	0	17
pull_request	0	0	0	0	0	0	0	17
Δ	0	0	0	0	0	0	0	0
Improvement %	0	0	0	0	0	0	0	0

ValkeyCommandEncoder – Command with 7 words metrics

Malloc (total): results within specified thresholds, fold down for details.

Malloc (total) *	p0	p25	p50	p75	p90	p99	p100	Samples
main	0	0	0	0	0	0	0	830
pull_request	0	0	0	0	0	0	0	824
Δ	0	0	0	0	0	0	0	-6
Improvement %	0	0	0	0	0	0	0	-6

ValkeyCommandEncoder – Simple GET metrics

Malloc (total): results within specified thresholds, fold down for details.

Malloc (total) *	p0	p25	p50	p75	p90	p99	p100	Samples
main	0	0	0	0	0	0	0	1971
pull_request	0	0	0	0	0	0	0	1985
Δ	0	0	0	0	0	0	0	14
Improvement %	0	0	0	0	0	0	0	14

ValkeyCommandEncoder – Simple MGET 15 keys metrics

Malloc (total): results within specified thresholds, fold down for details.

Malloc (total) *	p0	p25	p50	p75	p90	p99	p100	Samples
main	0	0	0	0	0	0	0	375
pull_request	0	0	0	0	0	0	0	377
Δ	0	0	0	0	0	0	0	2
Improvement %	0	0	0	0	0	0	0	2