code: @SuppressWarnings("unchecked")
      public static <T> T[] plus(T[] left, Collection<T> right) {
          return (T[]) plus((List<T>) toList(left), (Collection<T>) right).toArray();
      }
docs: Create an array containing elements from an original array plus those from a Collection.
  <pre class="groovyTestCase">
  Integer[] a = [1, 2, 3]
  def additions = [7, 8]
  assert a + additions == [1, 2, 3, 7, 8] as Integer[]
  </pre>
  
  @param left  the array
  @param right a Collection to be appended
  @return A new array containing left with right appended to it.
  @since 1.8.7