add cgroups options

cgroups/cpu.go

@@ -11,11 +11,27 @@ import (
 	"go.opentelemetry.io/otel/metric"
 )
 
-// Option supports configuring optional settings for runtime metrics.
-type Option interface {
-	apply(*config)
+func WithProvider(provider metric.MeterProvider) Option {
+	return func(c *config) {
+		c.provider = provider
+	}
 }
 
+func WithPrefic(name string) Option {
+	return func(c *config) {
+		c.prefix = name
+	}
+}
+
+func WithControllers(ctrls ...Controller) Option {
+	return func(c *config) {
+		c.controllers = ctrls
+	}
+}
+
+// Option supports configuring optional settings for runtime metrics.
+type Option func(*config)
+
 func newConfig(controllers []Controller, opts ...Option) config {
 	cfg := config{
 		controllers: controllers,
@@ -24,7 +40,7 @@ func newConfig(controllers []Controller, opts ...Option) config {
 	}
 
 	for _, opt := range opts {
-		opt.apply(&cfg)
+		opt(&cfg)
 	}
 
 	return cfg