Explicitly drop events events to the master if no session exists

Since the connector refactor the action of sending a message on a
connector that is in the process of connecting changed from queuing up
the message to send it to throwing an error.  To avoid events forwarded
by the slave to to the master when the connection is down from being
logged as an error forwardEventToMaster has to explicitly drop them.

packages/lib/link/connectors.js

@@ -163,6 +163,14 @@ class WebSocketBaseConnector extends events.EventEmitter {
 	get closing() {
 		return this._closing || this._state === "closed";
 	}
+
+	/**
+	 * True if the connector currently has a valid session that is either
+	 * connected or in the process of resuming.
+	 */
+	get hasSession() {
+		return ["connected", "resuming"].includes(this._state);
+	}
 }
 
 /**

packages/slave/slave.js

@@ -945,6 +945,10 @@ class InstanceConnection extends libLink.Link {
 	}
 
 	async forwardEventToMaster(message, event) {
+		if (!this.slave.connector.hasSession) {
+			return;
+		}
+
 		event.send(this.slave, message.data);
 	}