Package expvar provides a standardized interface to public variables, such as operation counters in servers. It exposes these variables via HTTP at /debug/vars in JSON format.
expvar - The Go Programming Language
Package expvar provides a standardized interface to public variables, such as operation counters in servers. It exposes these variables via HTTP at /debug/vars in JSON format. Operations to set or modify these public variables are atomic.
https://golang.org/pkg/expvar/
