Address TODOs to bring back the metric global package

[MrAlias]

Blocked by #2750 which adds back the Meter function.

TODOs

• opentelemetry-go/sdk/metric/benchmark_test.go

  Lines 184 to 204 in bbcdc75

  	// TODO readd global
  	// func BenchmarkGlobalInt64CounterAddWithSDK(b *testing.B) {
  	// // Compare with BenchmarkInt64CounterAdd() to see overhead of global
  	// // package. This is in the SDK to avoid the API from depending on the
  	// // SDK.
  	// ctx := context.Background()
  	// fix := newFixture(b)
  	// sdk := global.Meter("test")
  	// global.SetMeterProvider(fix)
  	// labs := []attribute.KeyValue{attribute.String("A", "B")}
  	// cnt := Must(sdk).NewInt64Counter("int64.sum")
  	// b.ResetTimer()
  	// for i := 0; i < b.N; i++ {
  	// cnt.Add(ctx, 1, labs...)
  	// }
  	// }

• opentelemetry-go/exporters/otlp/otlpmetric/otlpmetricgrpc/example_test.go

  Lines 56 to 57 in bbcdc75

  	// TODO Bring back Global package
  	// global.SetMeterProvider(pusher)

• opentelemetry-go/exporters/otlp/otlpmetric/otlpmetricgrpc/example_test.go

  Lines 71 to 72 in bbcdc75

  	// TODO Bring Back Global package
  	// meter := global.Meter("go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc_test")

• opentelemetry-go/exporters/otlp/otlpmetric/otlpmetricgrpc/example_test.go

  Lines 118 to 119 in bbcdc75

  	// TODO Bring back Global package
  	// global.SetMeterProvider(pusher)

• opentelemetry-go/exporters/otlp/otlpmetric/otlpmetricgrpc/example_test.go

  Lines 134 to 135 in bbcdc75

  	// TODO Bring back Global package
  	// meter := global.Meter("go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc_test")

• opentelemetry-go/exporters/otlp/otlpmetric/otlpmetricgrpc/example_test.go

  Lines 177 to 178 in bbcdc75

  	// TODO Bring back Global package
  	// global.SetMeterProvider(pusher)

• opentelemetry-go/exporters/otlp/otlpmetric/otlpmetricgrpc/example_test.go

  Lines 192 to 193 in bbcdc75

  	// TODO Bring back Global package
  	// meter := global.Meter("go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc_test")

• opentelemetry-go/exporters/stdout/stdoutmetric/example_test.go

  Lines 36 to 40 in bbcdc75

  	// TODO Bring back Global package
  	// meter = global.GetMeterProvider().Meter(
  	// instrumentationName,
  	// metric.WithInstrumentationVersion(instrumentationVersion),
  	// )

• opentelemetry-go/exporters/stdout/stdoutmetric/example_test.go

  Lines 85 to 86 in bbcdc75

  	// TODO Bring back Global package
  	// global.SetMeterProvider(pusher)

• opentelemetry-go/exporters/stdout/stdoutmetric/example_test.go

  Line 108 in bbcdc75

  // TODO: Registers a meter Provider globally.

• opentelemetry-go/example/prometheus/main.go

  Line 39 in bbcdc75

  // TODO Bring back Global package

• opentelemetry-go/example/prometheus/main.go

  Lines 60 to 61 in bbcdc75

  	// TODO Bring back Global package
  	// global.SetMeterProvider(exporter.MeterProvider())

• opentelemetry-go/example/prometheus/main.go

  Lines 75 to 76 in bbcdc75

  	// TODO Bring back Global package
  	// meter := global.Meter("ex.com/basic")

[bradtopol]

Hi @MrAlias. As you mentioned in the weekly meeting, I am willing to look at handling this issue. I will contact you about it on slack.