What mechanisms make coroutines lighter and more resource-efficient?

Coroutines make asynchronous code execution easier and more efficient through the following mechanisms:

• Lightweight: Coroutines do not require allocating a separate OS thread, reducing overhead for context switching.

• Suspend/Resume: Coroutines can suspend execution without blocking a thread and resume later, allowing efficient resource utilization.

• Coroutine scheduler: The management of coroutine execution occurs at the language/library level, enabling optimization of switching between them.

• No blocking: Coroutines use non-blocking I/O operations, which improves scalability.

Example in Kotlin:

import kotlinx.coroutines.*

fun main() = runBlocking {
    launch {
        delay(1000L) // suspends the coroutine without blocking the thread
        println("Hello from coroutine!")
    }
    println("Starting coroutine")
}

Here, delay suspends the coroutine without blocking the thread, allowing other coroutines to run in parallel.