code: @NonNull
      @Override
      public MutableArray insertValue(int index, Object value) {
          synchronized (lock) {
              if (!internalArray.insert(index, Fleece.toCBLObject(value))) { throwRangeException(index); }
              return this;
          }
      }
docs: Inserts an object at the given index.
  
  @param index the index. This value must not exceed the bounds of the array.
  @param value the object
  @return The self object