Allow creating automatically updated gauges

[ivantopo]

We should have a way to let users create a gauge and provide a function that will produce a value for it and automatically schedule a action that pulls the value from the function and updates the gauge.

This has been showing up several times recently and I don't see any reason for us not to do it. /cc @pjfanning

[ivantopo]

Additionally to the above, we should have a "sampler" that can do a similar job as the proposed auto-updated gauge but instead of updating the gauge it would be storing all the values in a Histogram. This would be the same as the Gauge in the 0.6 series.

[ivantopo]

I'm closing this issue because it is either too old to be relevant or stale. Stop by our Github Discussions section and drop a message if you need any additional help with the topic.

Have a nice day!