add annotations and assert to help static code analysis

src/main/java/io/reactivex/internal/operators/observable/ObservableWithLatestFromMany.java

@@ -16,6 +16,8 @@
 import java.util.concurrent.atomic.*;
 
 import io.reactivex.*;
+import io.reactivex.annotations.NonNull;
+import io.reactivex.annotations.Nullable;
 import io.reactivex.disposables.Disposable;
 import io.reactivex.exceptions.Exceptions;
 import io.reactivex.functions.Function;
@@ -33,20 +35,23 @@
  */
 public final class ObservableWithLatestFromMany<T, R> extends AbstractObservableWithUpstream<T, R> {
 
+    @Nullable
     final ObservableSource<?>[] otherArray;
 
+    @Nullable
     final Iterable<? extends ObservableSource<?>> otherIterable;
 
+    @NonNull
     final Function<? super Object[], R> combiner;
 
-    public ObservableWithLatestFromMany(ObservableSource<T> source, ObservableSource<?>[] otherArray, Function<? super Object[], R> combiner) {
+    public ObservableWithLatestFromMany(@NonNull ObservableSource<T> source, @NonNull ObservableSource<?>[] otherArray, @NonNull Function<? super Object[], R> combiner) {
         super(source);
         this.otherArray = otherArray;
         this.otherIterable = null;
         this.combiner = combiner;
     }
 
-    public ObservableWithLatestFromMany(ObservableSource<T> source, Iterable<? extends ObservableSource<?>> otherIterable, Function<? super Object[], R> combiner) {
+    public ObservableWithLatestFromMany(@NonNull ObservableSource<T> source, @NonNull Iterable<? extends ObservableSource<?>> otherIterable, @NonNull Function<? super Object[], R> combiner) {
         super(source);
         this.otherArray = null;
         this.otherIterable = otherIterable;
@@ -58,6 +63,7 @@ protected void subscribeActual(Observer<? super R> s) {
         ObservableSource<?>[] others = otherArray;
         int n = 0;
         if (others == null) {
+            assert otherIterable!=null;
             others = new ObservableSource[8];
 
             try {