Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

@JvmName("flatMapIndexedIterableTo") inline fun <R, C : MutableCollection<in R>> CharSequence.flatMapIndexedTo(
    destination: C, 
    transform: (index: Int, Char) -> Iterable<R>
): C

Appends all elements yielded from results of transform function being invoked on each character and its index in the original char sequence, to the given destination.