code: boolean setRequestSequence(long requestSequence) {
      if (requestSequence == this.requestSequence + 1) {
        this.requestSequence = requestSequence;
        return true;
      } else if (requestSequence <= this.requestSequence) {
        return true;
      }
      return false;
    }
docs: Checks and sets the current request sequence number.
  
  @param requestSequence The request sequence number to set.
  @return Indicates whether the given {@code requestSequence} number is the next sequence number.