APM Agent language and version:
Description of the problem including expected versus actual behavior. Please include screenshots (if relevant):
I want to add system and runtime metrics in addition to default metrics by calling
GatherMetrics method (https://github.com/elastic/apm-agent-go/blob/95e54b2e24ea813e0d059e56dfe6c740681564cb/builtin_metrics.go#L46) from Tracer but it looks there is no way to access it unless I'm mistaken. Do you think I missed something or is the method not exposed for consumption?