Go escape analysis and allocations test

escape_test.go

// go test -gcflags '-m' -benchmem -bench .
// BenchmarkAllocsFoo-4          	 5000000	       387 ns/op	      32 B/op	       1 allocs/op
// BenchmarkAllocsFooPointer-4   	 3000000	       481 ns/op	      80 B/op	       4 allocs/op
package main

import (
	"fmt"
	"io/ioutil"
	"testing"
)

type F func()

type CallsArgs struct {
	Concurrency int
	CallsNumber int
	Fn          F
}

func Foo(args CallsArgs) {}

func FooPointer(args *CallsArgs) {}

func BenchmarkAllocsFoo(b *testing.B) {
	for i := 0; i < b.N; i++ {
		args := CallsArgs{Concurrency: 1, CallsNumber: 42, Fn: func() {}}
		Foo(args)
		fmt.Fprintln(ioutil.Discard, args)
	}
}

func BenchmarkAllocsFooPointer(b *testing.B) {
	for i := 0; i < b.N; i++ {
		args := &CallsArgs{Concurrency: 1, CallsNumber: 42, Fn: func() {}}
		FooPointer(args)
		fmt.Fprintln(ioutil.Discard, args)
	}
}