Bind stdouttrace self-observability instruments

[MrAlias]

Alternative to #7215

Base on changes in #7222 and #7223.

This uses the github.com/MrAlias/bind package to bind reused attributes during instrument creation. This efficiently handles sending these values on the hot-path.

Additionally, the combination of #7223 and the bind package allow the error case to be as optimized as possible. The remaining allocations are from the new set allocations like in #7215. The difference here compared to #7215 is no additional pools are needed and the call-sites are not verbose.

Benchmarks

benchstat main.txt poc-bind-telemetry-stdouttrace.txt
goos: linux
goarch: amd64
pkg: go.opentelemetry.io/otel/exporters/stdout/stdouttrace
cpu: Intel(R) Core(TM) i7-8550U CPU @ 1.80GHz
                                        │   main.txt   │ poc-bind-telemetry-stdouttrace.txt │
                                        │    sec/op    │   sec/op     vs base               │
ExporterExportSpans/SelfObservability-8   31.35µ ± 17%   30.24µ ± 7%       ~ (p=0.143 n=10)
ExporterExportSpans/NoObservability-8     30.10µ ±  2%   30.36µ ± 2%       ~ (p=0.436 n=10)

                                        │   main.txt   │  poc-bind-telemetry-stdouttrace.txt  │
                                        │     B/op     │     B/op      vs base                │
ExporterExportSpans/SelfObservability-8   6.353Ki ± 0%   4.867Ki ± 0%  -23.38% (p=0.000 n=10)
ExporterExportSpans/NoObservability-8     4.765Ki ± 0%   4.765Ki ± 0%        ~ (p=1.000 n=10)

                                        │  main.txt  │ poc-bind-telemetry-stdouttrace.txt  │
                                        │ allocs/op  │ allocs/op   vs base                 │
ExporterExportSpans/SelfObservability-8   134.0 ± 0%   122.0 ± 0%  -8.96% (p=0.000 n=10)
ExporterExportSpans/NoObservability-8     119.0 ± 0%   119.0 ± 0%       ~ (p=1.000 n=10) ¹
¹ all samples are equal

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.9%. Comparing base (25d0274) to head (01eff24).

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #7226     +/-   ##
=======================================
- Coverage   83.0%   82.9%   -0.1%     
=======================================
  Files        265     265             
  Lines      24850   24811     -39     
=======================================
- Hits       20631   20589     -42     
- Misses      3839    3842      +3     
  Partials     380     380             

Files with missing lines	Coverage Δ
exporters/stdout/stdouttrace/trace.go	88.8% <100.0%> (-2.7%)	⬇️

... and 2 files with indirect coverage changes

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[flc1125]

If we refer to the tracer, we could pre-set some values at creation time, like this:

package main

import (
	"context"

	"go.opentelemetry.io/otel/attribute"
	"go.opentelemetry.io/otel/metric"
	"go.opentelemetry.io/otel/trace"
)

func main() {
	var (
		tracer trace.Tracer
		meter metric.Meter
	)

	tracer.Start(
		context.TODO(),
		"operationName",
		trace.WithAttributes(attribute.String("key", "value")), // <--- Refer to a design similar to this one
	)

	meter.Float64Counter(
		"example.com/metric",
		metric.WithDescription("An example metric"),
		metric.WithAttributeSet(attribute.NewSet(...)), //
		metric.WithAttributes(attribute.String()...)),
	)
}

[MrAlias]

If we refer to the tracer, we could pre-set some values at creation time, like this:

package main

import (
	"context"

	"go.opentelemetry.io/otel/attribute"
	"go.opentelemetry.io/otel/metric"
	"go.opentelemetry.io/otel/trace"
)

func main() {
	var (
		tracer trace.Tracer
		meter metric.Meter
	)

	tracer.Start(
		context.TODO(),
		"operationName",
		trace.WithAttributes(attribute.String("key", "value")), // <--- Refer to a design similar to this one
	)

	meter.Float64Counter(
		"example.com/metric",
		metric.WithDescription("An example metric"),
		metric.WithAttributeSet(attribute.NewSet(...)), //
		metric.WithAttributes(attribute.String()...)),
	)
}

Attributes are not a part of an instrument's definition: https://github.com/open-telemetry/opentelemetry-go/blob/metric/v1.37.0/metric/syncfloat64.go#L32

We would first need to resolution on open-telemetry/opentelemetry-specification#4126 before we could change the API.