Challenge 3: Choosing a Dispatcher — Solution

import kotlinx.coroutines.*

suspend fun simulateNetworkCall(): String = withContext(Dispatchers.IO) {
    delay(300)
    "Response from server"
}

fun main() = runBlocking {
    val result = simulateNetworkCall()
    println(result)
}

/*
Output:
Response from server

Notes:
- Dispatchers.IO is used here (not Dispatchers.Default) because this
  function represents a network call — work that spends almost all of
  its time waiting on something external (the network), not work that
  keeps a CPU core busy computing. Dispatchers.IO's larger, elastic
  thread pool is designed exactly for this kind of blocking-wait work.
- Dispatchers.Default would be the right choice instead if this function
  were doing genuine CPU-bound work, like sorting a large list or parsing
  a big file, where a CPU core really is kept busy the whole time.
- withContext(Dispatchers.IO) { ... } both switches to the IO dispatcher
  for the block and returns its final expression as the function's
  result, which is why simulateNetworkCall() can be written as a
  single-expression function.
*/