Introduce OptionFuture helpers

Optimize user directory searches

src/core/utils/option.rs

@@ -0,0 +1,11 @@
+use futures::future::OptionFuture;
+
+pub trait OptionExt<T> {
+	fn map_async<O: Future, F: FnOnce(T) -> O>(self, f: F) -> OptionFuture<O>;
+}
+
+impl<T> OptionExt<T> for Option<T> {
+	fn map_async<O: Future, F: FnOnce(T) -> O>(self, f: F) -> OptionFuture<O> {
+		OptionFuture::<_>::from(self.map(f))
+	}
+}