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

inline fun <T, R, C : MutableCollection<in R>> Sequence<T>.flatMapTo(
    destination: C, 
    transform: (T) -> Sequence<R>
): C

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

The operation is terminal.