/**
 * [[VideoFrameProcessorPipelineObserver]] is the observer for {@link VideoFrameProcessorPipeline} to receive lifecycle or performance callbacks.
 */
export default interface VideoFrameProcessorPipelineObserver {
    /**
     * `processingDidStart` will be called when {@link VideoFrameProcessorPipeline} starts streaming.
     */
    processingDidStart?(): void;
    /**
     * `processingDidFailToStart` will be called when {@link VideoFrameProcessorPipeline} could not start streaming due to runtime errors.
     */
    processingDidFailToStart?(): void;
    /**
     * `processingDidStop` will be called when {@link VideoFrameProcessorPipeline} stops streaming expectedly.
     */
    processingDidStop?(): void;
    /**
     * `processingLatencyTooHigh` will be called when the execution of {@link VideoFrameProcessorPipeline} slows the frame rate down by half.
     */
    processingLatencyTooHigh?(latencyMs: number): void;
}