counterOf

fun <T> counterOf(): Counter<T>
fun <T> counterOf(vararg keys: Pair<T, Int>): Counter<T>
fun counterOf(s: CharSequence): Counter<Char>
fun <T> counterOf(items: Array<T>): Counter<T>
fun <T> counterOf(items: Iterator<T>): Counter<T>
fun <T> counterOf(items: Iterable<T>): Counter<T>