Slow update time when many requests are sent.

[ibdafna]

Each time a request is sent to Flask, WebDash queues a callback function which gets called whenever the next response is received from the back-end (this is synchronous by nature). Whenever many requests are sent at any given time (can be done by hovering over many data points in a short period of time in the cross_filter_app application), WebDash slows down considerably before processing and displaying the last response. We should investigate why this is happening. I suspect it could be related to the overly simple queue "implementation" (in quotation marks because it's a simple array) we're using:

webdash/src/worker-loader.ts

Lines 10 to 22 in 9857988

	class ResponseQueue {
	constructor() {
	this.queue = [];
	}
	enqueue(onSuccessFn: Function) {
	return this.queue.push(onSuccessFn);
	}
	dequeue() {
	return this.queue.shift();
	}
	queue: Array<Function>;
	}

[ibdafna]

@ivanov Any ideas on that one? Do you think it could be the excessive pushing/shifting operations on the queue? Could potentially use a linked list here