With client_golang v1.12.2, we removed the runtime/metrics from the default collector.

But now it seems difficult to get these metrics back without having to abandon the default registry. This makes the use of promauto more cumbersome.

Some ideas:

• Add a default registry method to adjust what metrics features are enabled at build time/runtime.
• Add some filtering methods so that only specific sets of runtime/metrics are included.

For example, of the new metrics I only need /sched/latencies:seconds right now.