Improve setAnimation docs

lottie/src/main/java/com/airbnb/lottie/LottieAnimationView.java

diff --git a/lottie/src/main/java/com/airbnb/lottie/LottieAnimationView.java b/lottie/src/main/java/com/airbnb/lottie/LottieAnimationView.java
index 1acd9d0..4c3513e 100644
--- a/lottie/src/main/java/com/airbnb/lottie/LottieAnimationView.java
+++ b/lottie/src/main/java/com/airbnb/lottie/LottieAnimationView.java
@@ -420,7 +420,10 @@
 
   /**
    * @see #setAnimation(JsonReader) which is more efficient than using a JSONObject.
-   * For animations loaded from the network, use {@link #setAnimationFromJson(String)}
+   * For animations loaded from the network, use {@link #setAnimationFromJson(String)}.
+   *
+   * If you must use a JSONObject, you can convert it to a StreamReader with:
+   *    `new JsonReader(new StringReader(json.toString()));`
    */
   @Deprecated
   public void setAnimation(JSONObject json) {

lottie/src/main/java/com/airbnb/lottie/LottieComposition.java

diff --git a/lottie/src/main/java/com/airbnb/lottie/LottieComposition.java b/lottie/src/main/java/com/airbnb/lottie/LottieComposition.java
index 33c0edb..e2df5a7 100644
--- a/lottie/src/main/java/com/airbnb/lottie/LottieComposition.java
+++ b/lottie/src/main/java/com/airbnb/lottie/LottieComposition.java
@@ -37,7 +37,7 @@
  */
 public class LottieComposition {
 
-  final PerformanceTracker performanceTracker = new PerformanceTracker();
+  private final PerformanceTracker performanceTracker = new PerformanceTracker();
   final Map<String, List<Layer>> precomps = new HashMap<>();
   final Map<String, LottieImageAsset> images = new HashMap<>();
   /** Map of font names to fonts */
@@ -152,7 +152,7 @@
     return sb.toString();
   }
 
-  @SuppressWarnings({"WeakerAccess", "unused"})
+  @SuppressWarnings({"WeakerAccess"})
   public static class Factory {
     private Factory() {
     }