flat
inline fun <T, R> Provider<T>.flatMapNonNull(crossinline transform: (T) -> Provider<R>?): Provider<R?>
Creates and returns a new Provider that lazily maps to the value of the Provider returned by transform, or null if transform returns null.
transform should be a pure function.
The returned provider will only be stored in a WeakReference in the parent providers (this and the result of transform).