What is the main reason for using the suspend keyword in the Kotlin programming language?

The suspend keyword in Kotlin is used to denote functions that can be paused and resumed later without blocking the thread. It is the foundation of coroutines — a mechanism for asynchronous and non-blocking programming.

Using suspend allows writing asynchronous code that appears sequential, simplifying reading and maintenance. Such functions can perform long-running operations (e.g., network requests or input/output) without blocking the main thread.

Example:

suspend fun fetchData(): String {
    delay(1000) // pauses execution for 1 second without blocking
    return "Data loaded"
}