Messages in jsonrpc are not processed according to enqueue order

[nieyuyao]

i am using the latest jsonrpc to fix an issue with volar. i found that messages are sometimes not processed according to the order of messageQueue.
the relevant code is as follows

} finally {
	if (result instanceof Promise) {
		result.then(() => {
			inFlight--;
			triggerMessageQueue();
		}).catch((error) => {
			logger.error(`Processing message queue failed: ${error.toString()}`);
		});
	} else {
		inFlight--;
	}
	triggerMessageQueue();
}	

it seems that the last triggerMessageQueue statement should not be executed when the previous result is a Promise.