code: public I withClosedStart() {
  
          if (this.start.isInfinite()) {
              throw new IllegalStateException(
                  "Infinite past cannot be included.");
          } else if (this.start.isClosed()) {
              return this.getContext();
          } else {
              Boundary<T> b = Boundary.of(IntervalEdge.CLOSED, this.start.getTemporal());
              return this.getFactory().between(b, this.end);
          }
  
      }
docs: /*[deutsch]
  <p>Schlie&szlig;t die untere Grenze dieses Intervall ein. </p>
  
  @return  changed copy of this interval including lower boundary
  @throws  IllegalStateException if the start is infinite past
  @since   4.21