Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

inline fun <R, C : MutableCollection<in R>> CharSequence.flatMapTo(
    destination: C, 
    transform: (Char) -> Iterable<R>
): C

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