Method unsafeDoForward

guava/src/com/google/common/base/Converter.java:244–246

(@Nullable A a)

   */

  private @Nullable B unsafeDoForward(@Nullable A a) {
    return doForward(uncheckedCastNullableTToT(a));
  }

  private @Nullable A unsafeDoBackward(@Nullable B b) {
    return doBackward(uncheckedCastNullableTToT(b));