Try -Infinity for an immediate initial write.

src/lib/device.ts

@@ -123,7 +123,7 @@ export default abstract class Device extends js.global.EventEmitter {
 		this.purgeEvent = js.setInterval(this.purgeHandlers, this.timeoutMs, this);
 		this.heartbeatInterval = heartbeatInterval * 1000;
 		this.heartbeatEvent = -1;
-		this.lastWrite = Date.now();
+		this.lastWrite = -Infinity;
 		this.initTime = Date.now();
 		this.initTimeout = CONNECT_TIMEOUT * 1000;
 		this.queue = [];