@Test public void mapKeys() {

  array[0] = " 1";
  array[1] = "one";
  array[2] = "2 ";
  array[3] = "two";
  array[4] = " 3";
  array[5] = "three";
  Map<String, String> map = builder.mapKeys(o -> ((String) o).trim()).build(array);
  assertSize(map, 3);
  assertBaseCase(map);
  assertThat(map).containsOnly(
      entry("1", "one"),
      entry("2", "two"),
      entry("3", "three")
  );
  assertThat(map).hasToString(
      "UnsafeArrayMap{1=one,2=two,3=three}"
  );
  assertThat(map.get("1")).isEqualTo("one");
  assertThat(map.get("2")).isEqualTo("two");
  assertThat(map.get("3")).isEqualTo("three");
}