Coroutines

• Light weight thread 
• Coroutines can run parallel and can communicate with each other
• Coroutines consume less memory, performance is way better than threads  

Why we us Coroutines?

• Async work
• For multi threading 

How we do this?

• Use suspended on method and
• use coroutines to listen the result

What is Coroutine builder?

Coroutine builder are simple function that create coroutine and act as a bridge between real world and the suspended world. They are called on scope. There are three types of scopes

• lunch: lunch coroutine and forget
• async: Return a deferred object
• runBlocking: Run as Main thread

Coroutine scope and dispatchers

The scope object of a Coroutine dictates how long the coroutine should live and wait for results. There are four predefine scopes 

• Global
• lifecycle
• rememberCoroutine
• viewModel

We can also define custom scopes by passing a job and a Dispatcher

What is a job?

A job can be used as a handle to coroutine where we can track the wait time and cancel it. 

What is Dispatcher?

It is used to specify which thread a coroutine uses for its execution. One can specify the dispatcher to the builder.

Dispatcher types

• Main - UI
• Default - CPD
• IO - Networking or file access