addPostProcessor(postProcessor, priority) {
        let indexToInsertAt;
        for (indexToInsertAt = 0; indexToInsertAt < this.postProcessors.length; indexToInsertAt++) {
            if (this.postProcessors[indexToInsertAt].priority >= priority) {
                break;
            }
        }
        this.postProcessors.splice(indexToInsertAt, 0, {postProcessor, priority});
    }
Adds a post processor object
@param {object} postProcessor
@param {number} priority - guidelines 1 = before compression, 1000 = compression, 2000 = after compression