feat: add sendKeepAlive

src/Client.js

@@ -75,9 +75,7 @@ export class Client extends EventEmitter {
             // send packets periodically to keep the connection alive
             this.#keepAliveInterval = setInterval(async () => {
                 if ((Date.now() - this.#lastPacketDate) > 30000) {
-                    await this.#protoRequest(KeepAlive.create({
+                    await this.sendKeepAlive()
-                        data: Date.now()
-                    }))
                 }
             }, 15000)
 
@@ -123,6 +121,12 @@ export class Client extends EventEmitter {
         })
     }
 
+    async sendKeepAlive() {
+        return await this.#protoRequest(KeepAlive.create({
+            data: Date.now()
+        }))
+    }
+
     async #publish(port, flags) {
         const response = await this.#protoRequest(PublishRequest.create({
             port,