some missing comments
diff --git a/clientconn.go b/clientconn.go
index bf66914..9c2e983 100644
--- a/clientconn.go
+++ b/clientconn.go
@@ -89,6 +89,7 @@
 	}
 }
 
+// WithPicker returns a DialOption which sets a picker for connection selection.
 func WithPicker(p Picker) DialOption {
 	return func(o *dialOptions) {
 		o.picker = p
@@ -104,6 +105,8 @@
 	}
 }
 
+// WithInsecure returns a DialOption which disables transport security for this ClientConn.
+// Note that transport security is required unless WithInsecure is set.
 func WithInsecure() DialOption {
 	return func(o *dialOptions) {
 		o.insecure = true