add Time helper as well (#536)

ptr/ptr.go

@@ -47,3 +47,9 @@ func String(s string) *string {
 func Duration(t time.Duration) *time.Duration {
 	return &t
 }
+
+// Time is a helper for turning a const time.Time into a pointer for use in
+// API types that want *time.Duration.
+func Time(t time.Time) *time.Time {
+	return &t
+}

ptr/ptr_test.go

@@ -53,6 +53,13 @@ func TestString(t *testing.T) {
 	}
 }
 
+func TestTime(t *testing.T) {
+	want := time.Now().Add(time.Minute)
+	if got, want := *Time(want), want; got != want {
+		t.Errorf("got = %v, want: %v", got, want)
+	}
+}
+
 func TestDuration(t *testing.T) {
 	want := 42 * time.Second
 	gotPtr := Duration(want)