code: public <T1 extends Throwable, T2 extends Throwable, T3 extends Throwable> 
                  RuntimeException againAs(Class<T1> t1, Class<T2> t2, Class<T3> t3) 
                  throws T1, T2, T3 {
          return againAs(t1, t2, t3, NULL_EX);
      }
docs: Throws the {@linkplain #getResolvingCause() cause} if it is one of the
  specified types, otherwise returns a
  {@linkplain #asRuntimeException() runtime exception}.
  <p>
  Intended to be written as {@code throw e.againAs(IOException.class)}.
  @param <T1>
  @param <T2>
  @param <T3>
  @param t1
  @param t2
  @param t3
  @return runtime exception
  @throws T1
  @throws T2
  @throws T3