Global EventBus in GoLang

I am trying to learn GO and in doing so trying different concepts. Right now I am trying a PubSub approach, but within the application. I have an EventBus and I amd trying to pass the instance via Dependency Injection. However when I run the application nothing happens.

main

package main

import (
	"github.com/asaskevich/EventBus"
	modelA "interfaces/internal/modelA"
	modelB "interfaces/internal/modelB"
)

func main() {
	bus := EventBus.New()

	a := &modelA.Bus{EventBus: bus}
	a.Send()

	b := &modelB.Bus{
		EventBus: bus,
	}
	b.Receive()

}

internal/modelA

package modelA

import (
	"fmt"
	"github.com/asaskevich/EventBus"
)

type Bus struct {
	EventBus EventBus.Bus
}

type ModelAService interface {
	Run()
	Send()
}

func calculator(a int, b int) {
	fmt.Printf("ModelA "+"%d\n", a+b)
}

func (bus *Bus) Receive() {
	err := bus.EventBus.Subscribe("testMessageFromB", calculator)
	if err != nil {
		fmt.Printf("Error Receiving message...")
	}
}

func (bus *Bus) Send() {
	bus.EventBus.Publish("testMessageFromA", 33, 33)
}

internal/modelB

package modelB

import (
	"fmt"
	"github.com/asaskevich/EventBus"
)

type Bus struct {
	EventBus EventBus.Bus
}

type ModelBService interface {
	Run()
	Send()
}

func calculator(a int, b int) {
	fmt.Printf("ModelB "+"%d\n", a+b)
}

func (bus *Bus) Receive() {
	err := bus.EventBus.Subscribe("testMessageFromA", calculator)
	if err != nil {
		fmt.Printf("Error Receiving message...")
	}
}

func (bus *Bus) Send() {
	bus.EventBus.Publish("testMessageFromB", 33, 60)
}

You need to first Subscribe to a topic
then Publish (executes callback defined for a topic).

Try something like this:

func main() {
    bus := EventBus.New()

    a := &modelA.Bus{EventBus: bus}
    b := &modelB.Bus{EventBus: bus}

	b.Receive() // Subscribe
	a.Send()    // Publish
    // Unsubscribe
}

Also see the example:

func calculator(a int, b int) {
	fmt.Printf("%d\n", a + b)
}

func main() {
	bus := EventBus.New();
	bus.Subscribe("main:calculator", calculator);
	bus.Publish("main:calculator", 20, 40);
	bus.Unsubscribe("main:calculator", calculator);
}

My debugging structure and output:

Footnotes:
You may rename b.Receive() to b.Subscribe()
and a.Send() to a.Publish() for clarity.

See also gRPC: