code: public static Timestamp fromEpoch(long epochMillis) {
      return Timestamp
          .newBuilder()
          .setNanos((int) ((epochMillis % MILLIS_PER_SECOND) * NANOS_PER_MILLI))
          .setSeconds(epochMillis / MILLIS_PER_SECOND)
          .build();
    }
docs: Obtain the current time from the unix epoch
  
  @param epochMillis gives the current time in milliseconds since since the epoch
  @return a {@code Timestamp} corresponding to the ticker's current value