flush() {
    if (this.state === "loneValue") {
      this.appendInt32(-1)
      this.appendRawValue(this.lastValue)
    } else if (this.state === "repetition") {
      this.appendInt53(this.count)
      this.appendRawValue(this.lastValue)
    } else if (this.state === "literal") {
      this.appendInt53(-this.literal.length)
      for (let v of this.literal) this.appendRawValue(v)
    } else if (this.state === "nulls") {
      this.appendInt32(0)
      this.appendUint53(this.count)
    }
    this.state = "empty"
  }
Private method, do not call from outside the class.