code: static <T extends Temporal<? super T>> boolean isSimultaneous(
          Boundary<T> start,
          Boundary<T> end
      ) {
  
          if (start.mode == PAST) {
              return (end.mode == PAST);
          } else if (start.mode == FUTURE) {
              return (end.mode == FUTURE);
          } else if (end.mode == PAST) {
              return false;
          } else if (end.mode == FUTURE) {
              return false;
          } else {
              return start.temporal.isSimultaneous(end.temporal);
          }
  
      }
docs: <p>Rein temporaler Vergleich ohne Ansehen der open/closed-Bedingung. </p>
  
  @param   <T> generic temporal type
  @param   start   starting boundary
  @param   end     ending boundary
  @return  {@code true} if start is simultaneous to end else {@code false}
  @since   2.0