Feature: add custom DNS support (#56)

common/picker/picker.go

@@ -0,0 +1,22 @@
+package picker
+
+import "context"
+
+func SelectFast(ctx context.Context, in <-chan interface{}) <-chan interface{} {
+	out := make(chan interface{})
+	go func() {
+		select {
+		case p, open := <-in:
+			if open {
+				out <- p
+			}
+		case <-ctx.Done():
+		}
+
+		close(out)
+		for range in {
+		}
+	}()
+
+	return out
+}