This functionality is in beta and is subject to change. The design and code is considered to be less mature than official GA features. Elastic will take a best effort approach to fix any issues, but beta features are not subject to the support SLA of official GA features.
This is the
expvar metricset of the Golang module.
Golang can expose its variables by the expvar API. With this metricset, you can collect all the expvar-exposed variables.