Pre-size resulting list for DataLoader#loadMany

Author: dfa1

src/main/java/org/dataloader/DataLoader.java

@@ -561,7 +561,7 @@ public CompletableFuture<List<V>> loadMany(List<K> keys, List<Object> keyContext
         nonNull(keyContexts);
 
         synchronized (this) {
-            List<CompletableFuture<V>> collect = new ArrayList<>();
+            List<CompletableFuture<V>> collect = new ArrayList<>(keys.size());
             for (int i = 0; i < keys.size(); i++) {
                 K key = keys.get(i);
                 Object keyContext = null;