add get set fill macro

src/brightness.rs

@@ -0,0 +1,19 @@
+use crate::UniffiCustomTypeConverter;
+use servicepoint::Brightness;
+
+uniffi::custom_type!(Brightness, u8);
+
+impl UniffiCustomTypeConverter for Brightness {
+    type Builtin = u8;
+
+    fn into_custom(val: Self::Builtin) -> uniffi::Result<Self>
+    where
+        Self: Sized,
+    {
+        Ok(Brightness::saturating_from(val))
+    }
+
+    fn from_custom(obj: Self) -> Self::Builtin {
+        obj.into()
+    }
+}