_clearAcks() {
    Object.keys(this.acks).forEach((id) => {
      const isBuffered = this.sendBuffer.some((packet) => String(packet.id) === id);
      if (!isBuffered) {
        const ack = this.acks[id];
        delete this.acks[id];
        if (ack.withError) {
          ack.call(this, new Error("socket has been disconnected"));
        }
      }
    });
  }
Clears the acknowledgement handlers upon disconnection, since the client will never receive an acknowledgement from
the server.

@private