BEP refactor (helidon-io#2285)

* Alex's BEP refactor

Signed-off-by: Daniel Kec <daniel.kec@oracle.com>

Author: danielkec

common/reactive/src/main/java/io/helidon/common/reactive/BiConsumerChain.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020 Oracle and/or its affiliates.
+ * Copyright (c) 2020, 2021 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -30,13 +30,6 @@ public void accept(T t, S s) {
         }
     }
 
-    BiConsumerChain<T, S> combineWith(BiConsumer<? super T, ? super S> another) {
-        BiConsumerChain<T, S> newChain = new BiConsumerChain<>();
-        newChain.addAll(this);
-        newChain.add(another);
-        return newChain;
-    }
-
     static <T, S> BiConsumer<T, S> combine(
             BiConsumer<T, S> current,
             BiConsumer<T, S> another) {
@@ -46,12 +39,18 @@ static <T, S> BiConsumer<T, S> combine(
         if (another == null) {
             return current;
         }
+        BiConsumerChain<T, S> newChain = new BiConsumerChain<>();
         if (current instanceof BiConsumerChain) {
-            return ((BiConsumerChain<T, S>) current).combineWith(another);
+            newChain.addAll((BiConsumerChain<T, S>) current);
+        } else {
+            newChain.add(current);
+        }
+
+        if (another instanceof BiConsumerChain) {
+            newChain.addAll((BiConsumerChain<T, S>) another);
+        } else {
+            newChain.add(another);
         }
-        BiConsumerChain<T, S> newChain = new BiConsumerChain<>();
-        newChain.add(current);
-        newChain.add(another);
         return newChain;
     }
 }