Remove memory pooling #138

Benchdiff Results

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

HEAD sha: 02a07dc

Base sha: 7a3cb02

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=json	25398.5	1%	25943	9%	~	(p=0.905 n=4+5)
Encode/format=json-2	13175.2	0%	13324.2	5%	~	(p=0.905 n=4+5)
Encode/format=vtproto	4790.4	0%	4774.4	0%	~	(p=0.151 n=5+5)
Encode/format=vtproto-2	2669.8	11%	2593.8	1%	~	(p=0.952 n=5+5)
Decode/format=json	122983	2%	122668	2%	~	(p=1.000 n=5+5)
Decode/format=json-2	64932.8	1%	65051.2	1%	~	(p=0.421 n=5+5)
Decode/format=vtproto	20447.8	1%	19400.2	0%	-5.12%	(p=0.008 n=5+5)
Decode/format=vtproto-2	12174	3%	12332	6%	~	(p=0.421 n=5+5)

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

name	old alloc/op (B/op)	±	new alloc/op (B/op)	±	delta	±
Encode/format=json	7592	0%	7592	0%	~	(all equal)
Encode/format=json-2	7593	0%	7593	0%	~	(all equal)
Encode/format=vtproto	3072	0%	3072	0%	~	(all equal)
Encode/format=vtproto-2	3072	0%	3072	0%	~	(all equal)
Decode/format=json	14281.8	0%	14282.6	0%	~	(p=0.437 n=5+5)
Decode/format=json-2	14282.2	0%	14281.4	0%	~	(p=0.524 n=5+5)
Decode/format=vtproto	12992.6	0%	12993	0%	~	(p=0.556 n=5+4)
Decode/format=vtproto-2	13031	0%	13031	0%	~	(all equal)

name	old allocs/op (allocs/op)	±	new allocs/op (allocs/op)	±	delta	±
Encode/format=json	26	0%	26	0%	~	(all equal)
Encode/format=json-2	26	0%	26	0%	~	(all equal)
Encode/format=vtproto	1	0%	1	0%	~	(all equal)
Encode/format=vtproto-2	1	0%	1	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	280.52	2%	277.24	4%	~	(p=0.341 n=5+5)
NDStreamDecoder-2	148.82	7%	148.22	4%	~	(p=0.802 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	15219.6	2%	14916	8%	~	(p=0.548 n=5+5)
APMEventToJSON/to-json-2	12335	0%	12430.4	1%	~	(p=0.056 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)