Make SetGroupingKey's hash configurable #197

Benchdiff Results

Benchmark Command: go test ./... -run ^ -bench . -count 5 -benchtime 100ms -cpu 1,2 -benchmem

HEAD sha: c55f99b

Base sha: d912d11

Degraded: false

pkg: github.com/elastic/apm-data/codec
goos: linux
goarch: amd64

name	old time/op (ns/op)	±	new time/op (ns/op)	±	delta	±
Encode/format=vtproto	4629.4	1%	4835.6	5%	+4.45%	(p=0.008 n=5+5)
Encode/format=vtproto-2	2506.75	1%	2602.4	2%	+3.82%	(p=0.016 n=4+5)
Encode/format=json	25617.4	3%	25801.4	2%	~	(p=0.548 n=5+5)
Encode/format=json-2	13224.8	1%	13473.2	6%	~	(p=0.222 n=5+5)
Decode/format=json	127947	4%	128547	3%	~	(p=0.841 n=5+5)
Decode/format=json-2	68189.4	3%	66850	2%	~	(p=0.421 n=5+5)
Decode/format=vtproto	19085.6	1%	18709.6	1%	-1.97%	(p=0.008 n=5+5)
Decode/format=vtproto-2	11914.8	18%	11165.4	3%	~	(p=0.095 n=5+5)

name	old bytes/op (bytes/op)	±	new bytes/op (bytes/op)	±	delta	±
Encode/format=vtproto	2775	0%	2775	0%	~	(all equal)
Encode/format=vtproto-2	2775	0%	2775	0%	~	(all equal)
Encode/format=json	6564	0%	6564	0%	~	(all equal)
Encode/format=json-2	6564	0%	6564	0%	~	(all equal)

name	old alloc/op (B/op)	±	new alloc/op (B/op)	±	delta	±
Encode/format=vtproto	3072	0%	3072	0%	~	(all equal)
Encode/format=vtproto-2	3072	0%	3072	0%	~	(all equal)
Encode/format=json	7592	0%	7592	0%	~	(all equal)
Encode/format=json-2	7593	0%	7593	0%	~	(all equal)
Decode/format=json	14282.6	0%	14282.6	0%	~	(p=0.857 n=5+5)
Decode/format=json-2	14281.4	0%	14281.6	0%	~	(p=1.000 n=5+5)
Decode/format=vtproto	12952	0%	12952	0%	~	(all equal)
Decode/format=vtproto-2	12952	0%	12952	0%	~	(all equal)

name	old allocs/op (allocs/op)	±	new allocs/op (allocs/op)	±	delta	±
Encode/format=vtproto	1	0%	1	0%	~	(all equal)
Encode/format=vtproto-2	1	0%	1	0%	~	(all equal)
Encode/format=json	26	0%	26	0%	~	(all equal)
Encode/format=json-2	26	0%	26	0%	~	(all equal)
Decode/format=json	379	0%	379	0%	~	(all equal)
Decode/format=json-2	379	0%	379	0%	~	(all equal)
Decode/format=vtproto	348	0%	348	0%	~	(all equal)
Decode/format=vtproto-2	348	0%	348	0%	~	(all equal)

pkg: github.com/elastic/apm-data/input/elasticapm/internal/decoder
goos: linux
goarch: amd64

name	old time/op (ns/op)	±	new time/op (ns/op)	±	delta	±
NDStreamDecoder	281.82	5%	282.82	5%	~	(p=0.730 n=5+5)
NDStreamDecoder-2	150.72	2%	150.46	5%	~	(p=0.206 n=5+5)

name	old alloc/op (B/op)	±	new alloc/op (B/op)	±	delta	±
NDStreamDecoder	72	0%	72	0%	~	(all equal)
NDStreamDecoder-2	72	0%	72	0%	~	(all equal)

name	old allocs/op (allocs/op)	±	new allocs/op (allocs/op)	±	delta	±
NDStreamDecoder	4	0%	4	0%	~	(all equal)
NDStreamDecoder-2	4	0%	4	0%	~	(all equal)

pkg: github.com/elastic/apm-data/model/modeljson
goos: linux
goarch: amd64

name	old time/op (ns/op)	±	new time/op (ns/op)	±	delta	±
APMEventToJSON/to-json	16723	8%	16076	11%	~	(p=0.222 n=5+5)
APMEventToJSON/to-json-2	13891.4	2%	13766.8	3%	~	(p=0.548 n=5+5)

name	old alloc/op (B/op)	±	new alloc/op (B/op)	±	delta	±
APMEventToJSON/to-json	2616	0%	2616	0%	~	(all equal)
APMEventToJSON/to-json-2	2616	0%	2616	0%	~	(all equal)

name	old allocs/op (allocs/op)	±	new allocs/op (allocs/op)	±	delta	±
APMEventToJSON/to-json	38	0%	38	0%	~	(all equal)
APMEventToJSON/to-json-2	38	0%	38	0%	~	(all equal)