// This should have no effect on existing escapers.
    builder.addEscape(' ', "*");

    // Test both escapers after modifying the builder.
    assertThat(first.escape("The Quick Brown Fox!")).isEqualTo("Xhe_Xuick_Xrown_XoxX");
    assertThat(second.escape("The Quick Brown Fox!")).isEqualTo("Xhe-Xuick-Xrown-Xox$");
  }

  // A trivial non-optimized escaper for testing.