import kotlinx.coroutines.sync.Semaphore
import kotlinx.coroutines.sync.withPermit

val semaphore = Semaphore(5, 5)

suspend fun main() {
    semaphore.acquire() //reduces available permits, suspends when none available
    semaphore.tryAcquire() //returns False if no permit available
    semaphore.release() //releases permit, possible after acquire

    semaphore.withPermit {

    }
}