src/vs/base/parts/ipc/common/ipc.net.ts/PersistentProtocol/_sendAck
class PersistentProtocol:	private _sendAck(): void {
		if (this._incomingMsgId <= this._incomingAckId) {
			// nothink to acknowledge
			return;
		}

		this._incomingAckId = this._incomingMsgId;
		const msg = new ProtocolMessage(ProtocolMessageType.Ack, 0, this._incomingAckId, getEmptyBuffer());
		this._socketWriter.write(msg);
	}