activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/btnEmit"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Emit" />

    <Button
        android:id="@+id/btnConsume1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Consume 1" />


    <Button
        android:id="@+id/btnConsume2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Consume 2" />


    <Button
        android:id="@+id/btnClose"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Close channel" />

</LinearLayout>

MainActivity.kt

import android.os.Bundle
import android.util.Log
import androidx.appcompat.app.AppCompatActivity
import androidx.lifecycle.lifecycleScope
import kotlinx.android.synthetic.main.activity_main.*
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.ExperimentalCoroutinesApi
import kotlinx.coroutines.FlowPreview
import kotlinx.coroutines.InternalCoroutinesApi
import kotlinx.coroutines.channels.BroadcastChannel
import kotlinx.coroutines.channels.Channel
import kotlinx.coroutines.channels.ConflatedBroadcastChannel
import kotlinx.coroutines.flow.asFlow
import kotlinx.coroutines.flow.launchIn
import kotlinx.coroutines.flow.onEach
import kotlinx.coroutines.launch


@ExperimentalCoroutinesApi
@FlowPreview
class MainActivity : AppCompatActivity() {

    private val publishChannel = BroadcastChannel<Int>(Channel.BUFFERED)
    private val behaviourChannel = ConflatedBroadcastChannel<Int>()
    private val tag = MainActivity::class.java.simpleName

    private var emitValue = 1

    @InternalCoroutinesApi
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        btnEmit.setOnClickListener {
            lifecycleScope.launch(Dispatchers.Default) {
                if (!publishChannel.isClosedForSend) {
                    publishChannel.send(emitValue++)
                } else {
                    log("channel closed")
                }
            }
        }

        btnConsume1.setOnClickListener {
            lifecycleScope.launch {
                consumeFirst()
            }
        }

        btnConsume2.setOnClickListener {
            lifecycleScope.launch {
                consumeSecond()
            }
        }

        btnClose.setOnClickListener {
            publishChannel.close()
        }
    }

    private fun consumeFirst() {
        publishChannel
            .asFlow()
            .onEach {
                log("consumeFirst value received:", it)
            }
            .launchIn(lifecycleScope)
    }

    private fun consumeSecond() {
        publishChannel
            .asFlow()
            .onEach {
                log("consumeSecond value received:", it)
            }
            .launchIn(this.lifecycleScope)
    }

    private fun log(message: String, arg: Any? = null) {
        Log.e(tag, "$message $arg")
    }

}