code: public boolean contains(long millisInstant) {
          long thisStart = getStartMillis();
          long thisEnd = getEndMillis();
          return (millisInstant >= thisStart && millisInstant < thisEnd);
      }
docs: Does this time interval contain the specified millisecond instant.
  <p>
  Non-zero duration intervals are inclusive of the start instant and
  exclusive of the end. A zero duration interval cannot contain anything.
  
  @param millisInstant  the instant to compare to,
  millisecond instant from 1970-01-01T00:00:00Z
  @return true if this time interval contains the millisecond