GitHub - ilius/go-mapsize: Estimate how much memory is occupied by a map.

go get github.com/ilius/go-mapsize

package main

import (
	"fmt"
	"github.com/ilius/go-mapsize"
)

func main() {
	m := make(map[int]struct{})
	for i := 0; i < 100; i++ {
		m[i] = struct{}{}
	}
	fmt.Println(mapsize.Size(m)) // 1344

	type A struct{}
	m2 := map[int]*A{}
	for i := 0; i < 100; i++ {
		m2[i] = &A{}
	}
	fmt.Println(mapsize.Size(m)) // 1344
}